tag:blogger.com,1999:blog-58155765659122814312024-03-10T20:23:35.691-07:00Norini Jaafar Chemistry-Portal for SPM students excel in their Chemistry-Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.comBlogger13125tag:blogger.com,1999:blog-5815576565912281431.post-85537859295153292552011-07-27T07:23:00.000-07:002011-07-27T07:23:32.731-07:00To make a hypothesisHow to construct or make a hypothesis?<br />
<br />
First, you must understand that a hypothesis is a statement that relates a <span style="color: red;">manipulated variable</span> with a <span style="color: red;">responding variable</span>.<br />
Therefore, you must be able to identify the manipulated variable and the responding variable for an experiment.<br />
<br />
For example, in experiment to determine the effect of temperature on the rate of reaction between sodium thiosulphate and sulphuric acid.<br />
<br />
The manipulated variable is temperature, and the responding variable is rate of reaction.<br />
<br />
Therefore, the statement of hypothesis is: When the temperature of sodium thiosulphate increases, the rate of reaction with sulphuric acid increases.Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-2641929729785379112011-07-25T06:46:00.000-07:002011-07-25T06:47:46.293-07:00Operational DefinitionOperational definition is a statement that shows the "what you do and what you observe".<br />
<br />
For example, the operational definition for coagulation of latex:<br />
<br />
The "what you do" is... when acid is added to latex..<br />
<br />
The "what you observe " is.... white solid is formed.<br />
<br />
Therefore the <strong>operational definition for the coagulation of latex</strong> is ..<strong><span style="color: #cc0000; font-family: "Trebuchet MS", sans-serif;">When acid is added to latex, white solid is formed. <span style="color: black;">(SPM 2008)</span></span></strong><br />
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<strong><span style="color: #cc0000; font-family: Trebuchet MS;">The operational definition for the neutralisation of acid or alkali could be... When acid is added to alkali with a few drops of phenolphthalein, the pink solution changes to colourless.</span></strong><br />
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<strong><span style="background-color: #f4cccc; color: #bf9000; font-family: Georgia, "Times New Roman", serif;">The operational definition for the reactivity of Group 1 elements towards water:</span></strong><br />
<strong><span style="background-color: #f4cccc; color: #bf9000; font-family: Georgia, "Times New Roman", serif;">When a metal which is lower down in Group 1is put into a basin filled with water, the movement of the metal on the water surface is faster // more vigorous// the flame produced is bigger or brighter.</span></strong><br />
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<strong><span style="color: black; font-family: Trebuchet MS;">Teacher Norini hopes that you girls and boys have some idea now the meaning of operational definition. Well, you can always ask Teacher Norini if you don't.</span></strong>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com5tag:blogger.com,1999:blog-5815576565912281431.post-50068385757805703282011-07-22T05:38:00.000-07:002011-07-22T05:38:39.155-07:00Constructs in Paper 3In Paper 3 Chemistry 4541/3, there are several constructs to be understood and solved.<br />
For example, making hypothesis, aim @ problem statement, naming variables, to state the operational definition and so on.<br />
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Question for the day!<br />
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<span style="color: #741b47; font-family: "Helvetica Neue", Arial, Helvetica, sans-serif;">What is operational definition?</span><br />
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For example: Give the operational definition for the <span style="color: #20124d;">neutralisation of acid and alkali.</span><br />
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<span style="color: red;">Teacher Norini will give the answer later....</span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-3967356146603400202011-07-18T19:59:00.000-07:002011-07-18T19:59:20.866-07:00Difference in pH value between hydrochloric acid and ethanoic acid.<span style="color: blue; font-family: Georgia, "Times New Roman", serif; font-size: large;">Answer</span><br />
<span style="font-size: large;">1. <span style="color: #0c343d;">Hydrochloric acid is a strong acid.</span></span><br />
<span style="color: #0c343d; font-size: large;">2. Therefore, acid can ionise completely in water </span><br />
<span style="color: #0c343d; font-size: large;">3. to produce high concentration of hydrogen ion</span><br />
<span style="color: #0c343d; font-size: large;">4. Ethanoic acid is a weak acid.</span><br />
<span style="color: #0c343d; font-size: large;">5. This acid can ionise partially in water</span><br />
<span style="color: #0c343d; font-size: large;">6. to produce low concentration of hydrogen ion</span><br />
<span style="font-size: large;"><span style="color: #0c343d;">7. When the concentration of hydrogen ion is higher, the pH value is</span> <span style="color: #073763;">lower</span></span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-77845880576652371082011-07-18T06:19:00.000-07:002011-07-18T06:19:41.855-07:00Salam boys and girls!<span style="color: red; font-family: Georgia, "Times New Roman", serif; font-size: large;">QUESTION FOR THE DAY.</span><br />
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<span style="background-color: #ffe599; font-family: Verdana, sans-serif; font-size: large;">Hydrochloric acid 1.0 mol dm-3 has 2 pH value.</span><br />
<span style="background-color: #ffe599; font-family: Verdana, sans-serif; font-size: large;">Ethanoic acid 1.0 mol dm-3 has 6 pH value.</span><br />
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<span style="background-color: #ffe599; font-family: Verdana, sans-serif; font-size: large;">Explain the difference in pH value for the acids</span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com1tag:blogger.com,1999:blog-5815576565912281431.post-17095858340818792222011-07-17T06:23:00.000-07:002011-07-17T06:23:40.123-07:00Salam. Sorry for the late reply for the answers to previous questions.<br />
Ok, the answer to why <span style="background-color: white; color: orange;">alloy is harder</span> than its's pure metal is:<br />
1.<span style="color: red;"> Atoms</span> of foreign element added to metal are of <span style="color: red;">different size</span> from atoms in pure metal.<br />
2. These atoms will <span style="color: red;">disrupt the orderly arrangement</span> of the atoms in metal.<br />
3. When force is applied, the foreign atoms will <span style="color: red;">reduce the sliding of the atoms over each other</span>.<br />
4. Thus making alloy harder and stronger.<br />
<br />
<span style="color: purple;">Pure metal</span> is soft, malleable and ductile because:<br />
1. <span style="color: red;">Atoms</span> are of the <span style="color: red;">same size</span><br />
2. Atoms are <span style="color: red;">arranged in layers and orderly manner</span>.<br />
3. When force is applied the<span style="color: red;"> layers of atoms can easily slide over each other</span><br />
<br />
<span style="background-color: #f4cccc; color: red;"><strong>Note: make sure you know how to draw the diagram for the arrangement of atoms in alloy and pure metal</strong></span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-21435376837990213242011-07-13T05:28:00.000-07:002011-07-13T05:28:37.829-07:00<div style="text-align: center;"><span style="color: #cc0000; font-family: "Trebuchet MS", sans-serif; font-size: large;">QUESTION FOR THE DAY</span></div><br />
<span style="font-family: "Trebuchet MS", sans-serif; font-size: large;"> <span style="color: #990000;">WHY IS ALLOY HARDER THAN IT'S PURE METAL?</span></span><br />
<br />
<br />
<span style="font-family: Trebuchet MS; font-size: large;">Teacher Norini will give the answer tomorrow. </span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com2tag:blogger.com,1999:blog-5815576565912281431.post-25378998772581141022011-07-12T02:10:00.000-07:002011-07-12T02:10:47.314-07:00More homework on Chemical Formulae and Equations<div class="MsoNormal" style="margin: 0cm 0cm 10pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">1(a) What is the meaning of empirical formula?</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">.....................................................................................................................................................</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">[1 mark]</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(ii) A carbon compound X has an empirical formula of CH<sub>2</sub> and a molar mass of 70 g mol<sup>-1</sup>. Determine the molecular formula of compound X.</span></div><br />
<br />
<br />
<div style="text-align: right;">[3 marks]</div><div align="left" style="text-align: right;"></div><br />
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(b) A group of students carried out an experiment to determine the empirical formula of magnesium oxide. </span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(i) Draw the apparatus set up for the experiment.</span></div><br />
<br />
<div style="text-align: right;">[2 marks]</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><rect id="_x0000_s1026" style="height: 82.5pt; left: 0px; margin-left: 27pt; margin-top: 22.85pt; position: absolute; text-align: left; width: 294.75pt; z-index: -1;"></rect><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"><span style="mso-spacerun: yes;"> </span>Diagram 1 shows the results of the experiment.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"><span style="mso-tab-count: 1;"> </span>Mass of crucible<span style="mso-spacerun: yes;"> </span>+ lid<span style="mso-spacerun: yes;"> </span>=<span style="mso-spacerun: yes;"> </span>24.88 g</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"><span style="mso-tab-count: 1;"> </span>Mass of crucible + lid + magnesium ribbon<span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span>=<span style="mso-spacerun: yes;"> </span>25.12 g</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"><span style="mso-tab-count: 1;"> </span>Mass of crucible + lid + magnesium oxide<span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span>=<span style="mso-spacerun: yes;"> </span>25.28 g</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"><span style="mso-spacerun: yes;"> </span></span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"><span style="mso-spacerun: yes;"> </span>Diagram 1</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(ii) Based on Diagram 1, complete Table 1 and determine the empirical formula of magnesium oxide.</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div style="text-align: left;"></div><table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-bottom: medium none; border-collapse: collapse; border-left: medium none; border-right: medium none; border-top: medium none; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-yfti-tbllook: 1184;"><tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;"><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: black 1pt solid; border-right: black 1pt solid; border-top: black 1pt solid; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Element</span></div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: black 1pt solid; mso-border-alt: solid black .5pt; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: center;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Mg</span></div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: black 1pt solid; mso-border-alt: solid black .5pt; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: center;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">O</span></div></td></tr>
<tr style="mso-yfti-irow: 1;"><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: black 1pt solid; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Mass (g)</span></div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td></tr>
<tr style="mso-yfti-irow: 2;"><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: black 1pt solid; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Number of moles</span></div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td></tr>
<tr style="mso-yfti-irow: 3;"><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: black 1pt solid; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Simplest ratio of moles</span></div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154.05pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td></tr>
<tr style="mso-yfti-irow: 4; mso-yfti-lastrow: yes;"><td style="background-color: transparent; border-bottom: black 1pt solid; border-left: black 1pt solid; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 154pt;" valign="top" width="205"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">Empirical Formula</span></div></td><td colspan="2" style="background-color: transparent; border-bottom: black 1pt solid; border-left: #f0f0f0; border-right: black 1pt solid; border-top: #f0f0f0; mso-border-alt: solid black .5pt; mso-border-bottom-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-right-themecolor: text1; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 308.1pt;" valign="top" width="411"><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div></td></tr>
</tbody></table><br />
<div align="center" class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: center;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">Table 1</span></div><div align="right" class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">[6 marks]</span></div><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"></span><br />
<div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(iii) Write the chemical equation for the reaction in the experiment.</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">......................................................................................................................................................</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">[1 mark]</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(c) Why the process of heating, cooling and weighing are repeated until constant mass is obtained?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">......................................................................................................................................................</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">......................................................................................................................................................</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">[1 mark]</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(d) Why this experiment is not suitable to be used to determine the empirical formula of copper(II) oxide?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: justify;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">......................................................................................................................................................</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: justify;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">......................................................................................................................................................</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">[1 mark]</span></div><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"></span><br />
<div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">2. A group of students carried out an experiment to determine the empirical formula <span style="mso-spacerun: yes;"> </span></span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"><span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span>of <span style="mso-spacerun: yes;"> </span>magnesium oxide.</span><br />
<br />
<div class="MsoNormal" style="margin: 0cm 0cm 10pt;"><span style="font-family: Times, "Times New Roman", serif;"><b style="mso-bidi-font-weight: normal;">Result</b> :</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: Times, "Times New Roman", serif;"><span style="mso-tab-count: 2;"> </span><span style="mso-spacerun: yes;"> </span>Mass of crucible + lid<span style="mso-tab-count: 4;"> </span><span style="mso-spacerun: yes;"> </span>= 24.0 g</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: Times, "Times New Roman", serif;"><span style="mso-tab-count: 2;"> </span><span style="mso-spacerun: yes;"> </span>Mass of crucible + lid + magnesium ribbon<span style="mso-tab-count: 2;"> </span>= 26.4 g</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt;"><span style="font-family: Times, "Times New Roman", serif;"><span style="mso-tab-count: 2;"> </span><span style="mso-spacerun: yes;"> </span>Mass of crucible + lid + magnesium oxide<span style="mso-tab-count: 2;"> </span>= 28.0 g</span></div><br />
<span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"> </span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">(a) What is meant by empirical formula?</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 413.25pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"><span style="mso-spacerun: yes;"> </span>…………………………………………………………………………………………………............................</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 413.25pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"> </span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 413.25pt; text-align: right;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;"> ........................</span><span style="font-family: "Times New Roman", "serif"; font-size: 12pt;">………………………………………………………………………………………………….<span style="mso-spacerun: yes;"> </span>[1 mark]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;">(b) Based on the above results,</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><span style="font-family: "Times New Roman", "serif"; font-size: 12pt; line-height: 115%;"><span style="mso-spacerun: yes;"> C</span>alculate the empirical formula of magnesium oxide.</span></div><div align="left" style="text-align: right;"></div><div style="text-align: right;">[3 markah]</div><div style="text-align: right;"></div><div style="text-align: right;"><br />
</div><div style="text-align: right;"><br />
</div><br />
<div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span style="font-family: Calibri;">(c) </span><span style="font-family: Times, "Times New Roman", serif;">write the chemical equation for the reaction in the experiment.</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span style="font-family: Calibri;">................................................................................................................................................................................</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: right;"><span style="font-family: Calibri;"><span style="mso-tab-count: 12;"> </span>[1 mark]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><span style="font-family: Times, "Times New Roman", serif;">(d) Why was the crucible lid opened once in a while during the experiment?</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span style="font-family: Calibri;">__________________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span style="font-family: Calibri;">__________________________________________________________________________________</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span style="font-family: Calibri;"><span style="mso-tab-count: 12;"> </span><span style="mso-spacerun: yes;"> </span>[ 1 mark]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><span style="font-family: Times, "Times New Roman", serif;">(e) Metal X is placed below hydrogen in the reactivity series. You are required to carry out an experiment<span style="mso-spacerun: yes;"> </span>to determine the empirical formula of the oxide of metal X. The apparatus provided are combustion<span style="mso-spacerun: yes;"> </span>tube, glass tube, cork, Bunsen burner and porcelain dish.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 10pt; tab-stops: 18.0pt;"><span style="font-family: Times, "Times New Roman", serif;">(i) draw a labelled diagram of the set-up of the apparatus for the experiment.</span></div><div align="left" style="text-align: right;"></div><div align="left" style="text-align: right;"></div><div style="text-align: right;">[2 marks]<br />
<div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: right;"><span style="font-family: Calibri;">(ii) Describe the steps that should be taken to ensure that all the air in the combustion tube has</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;">been </span><span style="font-family: Calibri;">expelled.</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: left;"><span style="font-family: Calibri;"><span style="mso-tab-count: 2;"> </span>_______________________________________________________________________________</span></div><div align="right" class="MsoNormal" style="line-height: normal; margin: 0cm 0cm 10pt; tab-stops: 18.0pt; text-align: right;"><span style="font-family: Calibri;"><span style="mso-tab-count: 13;"> </span><span style="mso-spacerun: yes;"> </span>[3 marks]</span></div><br />
<br />
<br />
</div><div style="text-align: right;"><br />
</div>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-85801692182163386312011-07-12T00:29:00.000-07:002011-07-12T00:29:37.751-07:00Homework for the weekend<div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">TOPIK: CHEMICAL FORMULAE AND </span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>EQUATION</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">1. </span><span lang="EN-US">The equation below represents the<span style="mso-spacerun: yes;"> </span></span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>reaction to extract aluminium from </span><span lang="EN-US">aluminium oxide.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><rect id="_x0000_s1027" style="height: 21pt; margin-left: 32.4pt; margin-top: 11.4pt; position: absolute; width: 165.6pt; z-index: -3;"></rect></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><line from="86.4pt,6.6pt" id="_x0000_s1026" style="position: absolute; z-index: 1;" to="122.4pt,6.6pt"><stroke endarrow="block"></stroke></line><span lang="EN-US"><span style="mso-spacerun: yes;"> <span lang="EN-US" style="font-family: "Times New Roman", "serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;">2Al<sub>3</sub>O<sub>3</sub><span style="mso-spacerun: yes;"> </span></span><span lang="EN-US" style="font-family: "Calibri", "sans-serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;">→ </span><span lang="EN-US" style="font-family: "Times New Roman", "serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;"><span style="mso-spacerun: yes;"> </span>4Al<span style="mso-spacerun: yes;"> </span>+<span style="mso-spacerun: yes;"> </span>3O<sub>2</sub></span></span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>What is the mass of aluminium that </span><span lang="EN-US">can be extracted from 102 g of </span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>aluminium oxide?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>[Relative atomic mass: O, 16 ; Al, 27]</span></div><ol style="margin-top: 0cm;" type="A"><li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l1 level1 lfo3; tab-stops: list 36.0pt;"><span lang="EN-US">13.5 g<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">C</b>.<span style="mso-spacerun: yes;"> </span>54.0 g</span></li>
<li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l1 level1 lfo3; tab-stops: list 36.0pt;"><span lang="EN-US">27.0 g<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">D</b>.<span style="mso-spacerun: yes;"> </span>108.0 g</span></li>
</ol><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><rect id="_x0000_s1029" style="height: 23.4pt; margin-left: 34.65pt; margin-top: 9pt; position: absolute; width: 162pt; z-index: -1;"></rect></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><line from="86.4pt,4.2pt" id="_x0000_s1028" style="position: absolute; z-index: 3;" to="131.4pt,4.2pt"><stroke endarrow="block"></stroke></line><span lang="EN-US">4.<span style="mso-spacerun: yes;"> <span lang="EN-US" style="font-family: "Times New Roman", "serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;">XCO<sub>3</sub><span style="mso-spacerun: yes;"> </span></span><span lang="EN-US" style="font-family: "Calibri", "sans-serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;">→</span><span lang="EN-US" style="font-family: "Times New Roman", "serif"; font-size: 12pt; mso-ansi-language: EN-US; mso-bidi-language: AR-SA; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-US;"><span style="mso-spacerun: yes;"> </span>XO<span style="mso-spacerun: yes;"> </span>+<span style="mso-spacerun: yes;"> </span>CO<sub>2</sub></span></span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 17.25pt;"><span lang="EN-US">The equation above shows the action of heat on the carbonate salt of metal X.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 17.25pt;"><span lang="EN-US">How many moles of XCO<sub>3</sub> are needed to produce 4.0 g of oxide X?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 17.25pt;"><span lang="EN-US">[Relative atomic mass: C, 12; O, 16; X, 64]</span></div><ol style="margin-top: 0cm;" type="A"><li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l2 level1 lfo4; tab-stops: list 36.0pt;"><span lang="EN-US">0.03<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">C.</b><span style="mso-spacerun: yes;"> </span>0.08</span></li>
<li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l2 level1 lfo4; tab-stops: list 36.0pt;"><span lang="EN-US">0.05<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">D</b>.<span style="mso-spacerun: yes;"> </span>0.09</span></li>
</ol><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">5.. What is the number of molecules in 1 </span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>mole of ammonia, NH<sub>3</sub>?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>[Avogadro’s constant: 6.0 x 10<sup>23</sup> mol<sup>-1</sup>]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 33pt; mso-list: l0 level1 lfo5; tab-stops: list 33.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">A.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1.5 x 10<sup>23</sup> molecules</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 33pt; mso-list: l0 level1 lfo5; tab-stops: list 33.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">B.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">6.0 x 10<sup>23</sup> molecules</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 33pt; mso-list: l0 level1 lfo5; tab-stops: list 33.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">C.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1.2 x 10<sup>24</sup> molecules</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 33pt; mso-list: l0 level1 lfo5; tab-stops: list 33.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">D.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">2.4 x 10<sup>24</sup> molecules</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">6. A compound with the formula X<sub>2</sub>CO<sub>3</sub> </span><span lang="EN-US">has a relative formula mass of 138.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>What is the relative atomic mass of X?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>[Relative atomic mass: C=12, O=16]</span></div><ol style="margin-top: 0cm;" type="A"><li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l4 level1 lfo6; tab-stops: list 36.0pt;"><span lang="EN-US">39<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">C.</b><span style="mso-spacerun: yes;"> </span>78</span></li>
<li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l4 level1 lfo6; tab-stops: list 36.0pt;"><span lang="EN-US">69<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">D.</b><span style="mso-spacerun: yes;"> </span>110</span></li>
</ol><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">7. The table shows the mass of elements M </span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>and O in an oxide, and the relative</span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>atomic mass<span style="mso-spacerun: yes;"> </span>of elements M and O.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><span lang="EN-US"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"></div><table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-bottom: medium none; border-collapse: collapse; border-left: medium none; border-right: medium none; border-top: medium none; margin: auto auto auto 23.4pt; mso-border-alt: solid windowtext .5pt; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-yfti-tbllook: 480;"><tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;"><td style="background: #d9d9d9; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 117pt;" valign="top" width="156"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Element</span></b></div></td><td style="background: #d9d9d9; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">M</span></b></div></td><td style="background: #d9d9d9; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">O</span></b></div></td></tr>
<tr style="mso-yfti-irow: 1;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 117pt;" valign="top" width="156"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Mass/g</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">5.6</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">2.4</span></div></td></tr>
<tr style="mso-yfti-irow: 2; mso-yfti-lastrow: yes;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 117pt;" valign="top" width="156"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Relative atomic mass</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">56</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 54pt;" valign="top" width="72"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">16</span></div></td></tr>
</tbody></table><br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"> The empirical formula for oxide M is </div><ol style="margin-top: 0cm;" type="A"><li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l0 level1 lfo1; tab-stops: list 36.0pt;"><span lang="EN-US">M<sub>2</sub>O<sub>3</sub><span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">C</b>. <span style="mso-spacerun: yes;"> </span>MO<sub>2</sub></span></li>
<li class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l0 level1 lfo1; tab-stops: list 36.0pt;"><span lang="EN-US">M<sub>2</sub>O<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">D</b>.<span style="mso-spacerun: yes;"> </span>MO</span></li>
</ol><span lang="EN-US"><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US">8. 5 g of element X reacted with 8<span style="mso-spacerun: yes;"> </span>of </span><span lang="EN-US">element Y to form a compound with the </span><span lang="EN-US">formula XY<sub>2</sub></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US"><span style="mso-tab-count: 1;"> </span>What is the relative atomic mass of </span><span lang="EN-US">element X?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US"><span style="mso-tab-count: 1;"> </span>[Relative atomic mass of Y=80]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l0 level1 lfo1; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">A.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">25<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">C</b>.<span style="mso-spacerun: yes;"> </span>50</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l0 level1 lfo1; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">B.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">40<span style="mso-tab-count: 3;"> </span><b style="mso-bidi-font-weight: normal;">D</b>.<span style="mso-spacerun: yes;"> </span>100</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">9. Which of the following statement is </span><span lang="EN-US">true for one mole of a substance?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 30pt; mso-list: l1 level1 lfo2; tab-stops: 18.0pt list 30.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">A.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1 mol of copper contains 6.02 x 10<sup>23</sup> molecules</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 30pt; mso-list: l1 level1 lfo2; tab-stops: 18.0pt list 30.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">B.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1 mol of oxygen gas contains 6.02 x 10<sup>23</sup> atoms</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 30pt; mso-list: l1 level1 lfo2; tab-stops: 18.0pt list 30.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">C.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1 mol of water contains the same number of atoms as in 12g of carbon-12</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 30pt; mso-list: l1 level1 lfo2; tab-stops: 18.0pt list 30.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">D.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1 mol of carbon dioxide contains the same number of molecules as the number of atoms in 12g of carbon-12</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 30pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US">10. Table below shows two elements and </span><span lang="EN-US">their respective relative atomic mass.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>The letters used are not the actual </span><span lang="EN-US">symbol of<span style="mso-spacerun: yes;"> </span>the elements.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US"></span><span lang="EN-US"></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; mso-list: l0 level1 lfo1; tab-stops: list 36.0pt;"></div><table border="1" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="border-bottom: medium none; border-collapse: collapse; border-left: medium none; border-right: medium none; border-top: medium none; margin: auto auto auto 23.4pt; mso-border-alt: solid windowtext .5pt; mso-border-insideh: .5pt solid windowtext; mso-border-insidev: .5pt solid windowtext; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-yfti-tbllook: 480;"><tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;"><td style="background: #d9d9d9; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 81pt;" valign="top" width="108"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">Element</span></b></div></td><td style="background: #d9d9d9; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 144pt;" valign="top" width="192"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">Relative atomic mass</span></b></div></td></tr>
<tr style="mso-yfti-irow: 1;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 81pt;" valign="top" width="108"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><span lang="EN-US">X</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 144pt;" valign="top" width="192"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><span lang="EN-US">24</span></div></td></tr>
<tr style="mso-yfti-irow: 2; mso-yfti-lastrow: yes;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 81pt;" valign="top" width="108"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><span lang="EN-US">M</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 144pt;" valign="top" width="192"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt; text-align: center;"><span lang="EN-US">12</span></div></td></tr>
</tbody></table><br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt; tab-stops: 18.0pt;"><span lang="EN-US"><span style="mso-tab-count: 1;"> </span>Which of<span style="mso-spacerun: yes;"> </span>the following is true about </span><span lang="EN-US">the atoms of elements X and M?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">A.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">The mass of 1 mol of X is twice the mass of 1 mol of M</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">B.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">1 mol of X has the same mass as 1 mol of M</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">C.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US"> <b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;"><span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">The mass of an atom of X is 24 g and the mass of an atom of M is 12 g</span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l0 level1 lfo1; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-list: Ignore;">D.<span style="font: 7pt "Times New Roman";"> </span></span></span></b><span lang="EN-US">The number of mole in 12 g of atom X is equal to the number of mole in 12 g of atom M.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">11. A balloon contains 6.02 x 10<sup>23</sup> of gas </span><span lang="EN-US">particles. What is the number of moles </span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>of the gas in the balloon?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>A </span></b><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>0.5 mol<span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">C</b><span style="mso-spacerun: yes;"> </span>3.0 mol</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>B </span></b><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>1.0 mol<span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">D</b><span style="mso-spacerun: yes;"> </span>6.0 mol</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">12. One mole of a substance is defined as </span><span lang="EN-US">the quantity of a substance that contains the same number of particles in <b style="mso-bidi-font-weight: normal;">m</b> g of element <b style="mso-bidi-font-weight: normal;">Y</b>.<span style="mso-spacerun: yes;"> </span>What are <b style="mso-bidi-font-weight: normal;">m</b> and <b style="mso-bidi-font-weight: normal;">Y</b>?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"></div><table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-bottom: medium none; border-collapse: collapse; border-left: medium none; border-right: medium none; border-top: medium none; margin: auto auto auto 26.7pt; mso-border-alt: solid windowtext .5pt; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; mso-yfti-tbllook: 1184;"><tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 21.25pt;" valign="top" width="28"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 35.45pt;" valign="top" width="47"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">m</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: windowtext 1pt solid; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 135.35pt;" valign="top" width="180"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Y</span></div></td></tr>
<tr style="mso-yfti-irow: 1;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 21.25pt;" valign="top" width="28"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">A</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 35.45pt;" valign="top" width="47"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">2</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 135.35pt;" valign="top" width="180"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Hydrogen - 1</span></div></td></tr>
<tr style="mso-yfti-irow: 2;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 21.25pt;" valign="top" width="28"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">B</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 35.45pt;" valign="top" width="47"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">12</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 135.35pt;" valign="top" width="180"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Carbon - 12</span></div></td></tr>
<tr style="mso-yfti-irow: 3;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 21.25pt;" valign="top" width="28"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">C</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 35.45pt;" valign="top" width="47"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">14</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 135.35pt;" valign="top" width="180"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Nitrogen - 14</span></div></td></tr>
<tr style="mso-yfti-irow: 4; mso-yfti-lastrow: yes;"><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: windowtext 1pt solid; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 21.25pt;" valign="top" width="28"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">D</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 35.45pt;" valign="top" width="47"><div align="center" class="MsoNormal" style="margin: 0cm 0cm 0pt; text-align: center;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">16</span></div></td><td style="background-color: transparent; border-bottom: windowtext 1pt solid; border-left: #f0f0f0; border-right: windowtext 1pt solid; border-top: #f0f0f0; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding-bottom: 0cm; padding-left: 5.4pt; padding-right: 5.4pt; padding-top: 0cm; width: 135.35pt;" valign="top" width="180"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US" style="mso-fareast-language: EN-MY;">Oxygen - 16</span></div></td></tr>
</tbody></table><br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt 36pt; mso-list: l2 level1 lfo3; tab-stops: 18.0pt list 36.0pt; text-indent: -18pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">13. When 6.4 g oxide of M reacted completely with hydrogen gas, 4.48 g of metal M is produced. What is the empirical formula of the oxide?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"> [Relative atomic mass:O,16; M,56]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="ES-TRAD" style="mso-ansi-language: ES-TRAD;">A</span></b><span lang="ES-TRAD" style="mso-ansi-language: ES-TRAD;"> MO <span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">C</b> M<sub>2</sub>O</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="ES-TRAD" style="mso-ansi-language: ES-TRAD;">B</span></b><span lang="ES-TRAD" style="mso-ansi-language: ES-TRAD;"> MO<sub>2</sub> <span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">D</b> M<sub>2</sub>O<sub>3</sub></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">14. Which of the following gases contains 0.4 mol of atoms at room temperature and pressure?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[1 mol of gas occupies the volume of 24 dm<sup>3</sup>at room temperature and pressure]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">A</span></b><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>4.8 dm<sup>3</sup> He<span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">C</b><span style="mso-spacerun: yes;"> </span>4.8 dm<sup>3</sup> SO<sub>3</sub></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">B</span></b><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>4.8 dm<sup>3</sup> H<sub>2</sub><span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">D</b><span style="mso-spacerun: yes;"> </span>4.8 dm<sup>3</sup> CO<sub>2</sub><span style="mso-spacerun: yes;"> </span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">15. The following equation shows the decomposition reaction of copper(II) carbonate when heated at room temperature and pressure.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"> CuCO<sub>3</sub><span style="mso-spacerun: yes;"> </span></span><span lang="EN-US" style="font-family: "Calibri", "sans-serif";">→</span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>CuO<span style="mso-spacerun: yes;"> </span>+<span style="mso-spacerun: yes;"> </span>CO<sub>2</sub></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">Which of the following is <b style="mso-bidi-font-weight: normal;">not</b> true when 1 mol of copper(II) carbonate is decomposed? </span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Relative atomic mass: C = 12, O=16, Cu = 64 and 1 mol of gas occupies the volume of 24 dm<sup>3</sup> at room temperature and pressure.]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">A</span></b><span lang="EN-US"> 1 mol of copper(II) oxide is formed</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">B</span></b><span lang="EN-US"> 1 molecule of carbon dioxide gas is </span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>given off</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">C</span></b><span lang="EN-US"> 80 g of copper(II) oxide is formed</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">D</span></b><span lang="EN-US"> 24 dm<sup>3</sup> of carbon dioxide gas is given</span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>off<span style="mso-spacerun: yes;"> </span></span></div><br />
<div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"><span lang="EN-US">16. Which of the following contains 6.02 x </span><span lang="EN-US">10<sup>23</sup> atoms?</span></span></span></div><span lang="EN-US"><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">A 1 mol of nitrogen gas</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">B 1 mol of chlorine gas</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">C 1 mol of ammonia gas</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">D 1 mol of neon gas</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> 17</span>. What is the number of moles of copper(II) nitrates in 56.4 g of copper(II) nitrate, Cu(NO<sub>3</sub>)<sub>2</sub>?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Relative atomic mass: O=16, Cu=64, N=14]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">A<span style="mso-spacerun: yes;"> </span>0.30 mol<span style="mso-spacerun: yes;"> </span>C<span style="mso-spacerun: yes;"> </span>0.45 mol</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">B<span style="mso-spacerun: yes;"> </span>0.32 mol<span style="mso-spacerun: yes;"> </span>D<span style="mso-spacerun: yes;"> </span>3.33 mol</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">18. Sodium reacts with chlorine to form sodium chloride.</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><rect filled="f" id="_x0000_s1026" style="height: 18.75pt; margin-left: 29.65pt; margin-top: -0.3pt; position: absolute; width: 118.5pt; z-index: 251672576;"></rect><span lang="EN-US"><span style="mso-tab-count: 1;"> </span>2Na<span style="mso-spacerun: yes;"> </span>+<span style="mso-spacerun: yes;"> </span>Cl<sub>2</sub><span style="mso-spacerun: yes;"> </span></span><span lang="EN-US" style="font-family: "Calibri", "sans-serif";">→</span><span lang="EN-US"><span style="mso-spacerun: yes;"> </span>2NaCl</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="mso-spacerun: yes;">19. </span>What is the mass of sodium chloride formed when 2.30 g of sodium reacts with excess chlorine?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Relative atomic mass: Na=23, Cl=35.5]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">A</span></b><span lang="EN-US"> 2.93g<span style="mso-tab-count: 1;"> </span><b style="mso-bidi-font-weight: normal;">C</b> 9.40g</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><b style="mso-bidi-font-weight: normal;"><span lang="EN-US">B </span></b><span lang="EN-US">5.85g<span style="mso-tab-count: 1;"> </span><b style="mso-bidi-font-weight: normal;">D</b> 11.70g</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">20. The relative molecular mass of M<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> is 342. What is the relative atomic mass of element M?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Relative atomic mass: O=16, S=32]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">A 27<span style="mso-tab-count: 2;"> </span>C 118</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">B 53<span style="mso-tab-count: 2;"> </span>D 123</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">21. A sample of iron oxide contains 5.6 g of iron and 2.4 g of oxygen. What is the empirical formula of this compound?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Relative atomic mass: O=16, Fe=56]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">A Fe<sub>2</sub>O<sub>3</sub><span style="mso-tab-count: 1;"> </span>C FeO<sub>2</sub></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">B Fe<sub>3</sub>O<sub>4</sub><span style="mso-tab-count: 1;"> </span>D FeO</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">22. What is the minimum mass of zinc required to react with excess hydrochloric acid to produce 240 cm<sup>3</sup> of hydrogen gas at room conditions?</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">[Molar volume of gas = 24 dm<sup>3</sup> mol<sup>-1</sup> at room conditions; </span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">Relative atomic mass: Zn = 65]</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">A 0.33 g<span style="mso-tab-count: 1;"> </span>C 1.30 g</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US">B 0.65 g<span style="mso-tab-count: 1;"> </span>D 6.50 g</span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
</div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="color: purple;">END OF QUESTIONS</span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="color: purple;">THANK YOU</span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="color: purple;">STEP UP YOUR EFFORTS TO ACHIEVE EXCELLENT RESULTS</span></span></div><div class="MsoNormal" style="margin: 0cm 0cm 0pt;"><br />
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</div></span> </span></span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com1tag:blogger.com,1999:blog-5815576565912281431.post-84551414967588906122011-05-08T04:48:00.000-07:002011-05-08T04:48:28.252-07:00Thoughts for the day<span style="color: red; font-family: "Helvetica Neue", Arial, Helvetica, sans-serif;">Keep on trying, no matter how difficult the task is. </span><br />
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<span style="color: red; font-family: "Helvetica Neue", Arial, Helvetica, sans-serif;">Keep going!!!</span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com1tag:blogger.com,1999:blog-5815576565912281431.post-13448026726202124152011-05-07T20:01:00.001-07:002011-05-07T20:01:41.048-07:00<span xmlns=''><p style='text-align: center'><strong>SALTS<br /></strong></p><p style='text-align: center'><strong>By NORINI BT JAAFAR<br /></strong></p><p style='text-align: center'><br /> </p><p style='text-align: justify'><strong>1.Definition:</strong> Salt is an ionic compound formed when the H<sup>+</sup> ion in an acid is replaced by a metal ion or an ammonium, NH<sub>4</sub><sup>+</sup> ion.<br /></p><p style='text-align: justify'>e.g. <span style='color:red'><strong>H</strong></span>Cl + <span style='color:green'><strong>Na</strong></span>OH → <span style='color:green'><strong>Na</strong></span>Cl + H<sub>2</sub>O<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>2. Salts can be classified into two main groups shown in Figure 1.<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: center'>SALTS<br /></p><p style='text-align: center'><br /> </p><p> Soluble Insoluble<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: justify'> <br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: center'>Figure 1<br /></p><p><br /> </p><p style='text-align: justify'>3. (a) <strong>Effects of heat on carbonate salts</strong>.<br /></p><p style='text-align: justify'> <br /> </p><p style='text-align: justify'> Carbonate salt → Metal oxide + CO<sub>2</sub><br /> </p><p style='text-align: justify'> Δ<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Example: Heating of copper(II) carbonate.<br /></p><p style='text-align: justify'> <br /> </p><p style='text-align: justify'>Chemical equation: CuCO<sub>3</sub> → CuO + CO<sub>2</sub><br /> </p><p style='text-align: justify'>Observations: i. <span style='color:green'><strong>Green</strong></span> solid of copper(II) carbonate turns <strong>black</strong> solid of copper(II) <br /></p><p style='text-align: justify'> oxide.<br /></p><p style='text-align: justify'> ii. Gas passed through lime water will turn lime water chalky.<br /></p><p style='text-align: justify'>Other examples: (a) <strong>PbCO<sub>3</sub> → PbO + CO<sub>2</sub></strong><br /> </p><p style='text-align: justify'><strong>Observations:</strong> i. Lead(II) oxide, PbO deposit is <span style='color:#ff6600'><strong>orange</strong></span> when <strong>hot</strong>, turns <span style='color:#ffcc00'><strong>yellow</strong></span> when <br /></p><p style='text-align: justify'><br /> <strong>cooled</strong>.<br /></p><p style='text-align: justify'> ii. Lime water turns chalky. <br /></p><p style='text-align: justify'> (b) <strong>ZnCO<sub>3</sub> → ZnO + CO<sub>2</sub><br /> </strong></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'><strong>Observations:</strong> i. Zinc oxide, ZnO deposit is <span style='color:#ffcc00'><strong>yellow</strong></span> when <strong>hot</strong>, turns <span style='color:#595959'><strong>white</strong></span> when <strong>cooled</strong>.<br /></p><p style='text-align: justify'> ii. Lime water turns chalky.<br /></p><p style='text-align: justify'>Note: All carbonates salt will be decomposed by heat to produce metal oxide and carbon dioxide <strong>except</strong> sodium carbonate, Na<sub>2</sub>CO<sub>3</sub> and potassium carbonate, K<sub>2</sub>CO<sub>3 </sub> which cannot be decomposed by heat.<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>3(b) <strong>Effects of heat on nitrate salt</strong>.<br /></p><p style='text-align: justify'> Nitrate salt → metal oxide + NO<sub>2</sub> + O<sub>2</sub><br /> </p><p style='text-align: justify'> Δ <br /></p><p style='text-align: justify'> <br /> </p><p style='text-align: justify'><sub><br /> </sub>Example: Heating of lead(II) nitrate, Pb(NO<sub>3</sub>)<sub>2</sub>.<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: center'><br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Chemical equation: <strong>2Pb(NO<sub>3</sub>)<sub>2</sub> → 2PbO + 4NO<sub>2</sub> + O<sub>2</sub><br /> </strong></p><p style='text-align: justify'><strong>Observations:</strong> i. Lead(II) oxide, PbO deposit is <strong>orange </strong>when <strong>hot</strong>, turns <strong>yellow</strong> when <br /></p><p style='text-align: justify; margin-left: 36pt'><strong>cooled.<br /></strong></p><p style='text-align: justify'> ii. When <strong>glowing wooden splinter</strong> is put inside the test tube, it <br /></p><p style='text-align: justify'><br /> <strong>rekindles</strong>.<br /></p><p style='text-align: justify'> Oxygen, O<sub>2</sub> gas produced.<br /></p><p style='text-align: justify'> iii. <strong>Brown gas</strong> released turns damp blue litmus paper to red.<br /></p><p style='text-align: justify'> Nitrogen dioxide, NO<sub>2</sub> gas produced.<br /></p><p style='text-align: justify'>Other examples: <strong>2Zn(NO<sub>3</sub>)<sub>2</sub> → 2 ZnO + 4NO<sub>2</sub> + O<sub>2</sub><br /> </strong></p><p style='text-align: justify'><strong> 2Cu(NO<sub>3</sub>)<sub>2</sub> → 2 CuO + 4NO<sub>2</sub> + O<sub>2</sub><br /> </strong></p><p style='text-align: justify'>Note: Sodium nitrate, NaNO<sub>3</sub> and potassium nitrate, KNO<sub>3</sub> when heated will decompose to produce nitrite salt and oxygen gas.<br /></p><p style='text-align: justify'> 2NaNO<sub>3</sub> → 2NaNO<sub>2</sub> + O<sub>2</sub><br /> </p><p style='text-align: justify'> 2KNO<sub>3</sub> → 2KNO<sub>2</sub> + O<sub>2<br /></sub></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>4. <strong>Preparation of Soluble Salts</strong><br /> </p><p style='text-align: justify'>Soluble salts can be prepared by the following methods:<br /></p><p style='text-align: justify'> (i) <strong>Neutralization</strong> reaction: Acid + Alkali → Salt + H<sub>2</sub>O<br /></p><p style='text-align: justify'> This method is suitable for sodium, potassium and ammonium salts.<br /></p><p style='text-align: justify'> (ii) <strong>Acids + Metal → Salts + H<sub>2</sub><br /> </strong></p><p style='text-align: justify'> This method is <strong>not</strong> suitable for salts when the metal is below hydrogen in the <br /></p><p style='text-align: justify'> Electrochemical Series, e.g copper.<br /></p><p style='text-align: justify'> (iii) <strong>Acid + Metal Oxide → Salt + H<sub>2</sub>O<br /></strong></p><p style='text-align: justify'> (iv) <strong>Acid + Metal Carbonates → Salt + H<sub>2</sub>O + CO<sub>2</sub><br /> </strong></p><p style='text-align: justify'>Example: <strong>To</strong><br /> <strong>prepare of copper(II) sulphate salt<br /></strong></p><p style='text-align: justify'>Substances: copper(II) oxide, sulphuric acid 1.0 mol dm<sup>-3</sup> solution.<br /></p><p style='text-align: justify'>Materials: beaker, 250 ml, filter funnel, glass rod, filter paper, evaporating dish, Bunsen burner, tripod stand, wire gauze.<br /></p><p style='text-align: justify'>Procedures:<br /></p><ol><li><div style='text-align: justify'>Pour (50 – 100) cm<sup>3</sup> of sulphuric acid solution into a beaker.<br /></div></li><li><div style='text-align: justify'>Heat the acid.<br /></div></li><li><div style='text-align: justify'>Copper(II) oxide powder is added into the acid until excess (to ensure that all the acid has completely reacted).<br /></div></li><li><div style='text-align: justify'>Stir the mixture.<br /></div></li><li><div style='text-align: justify'>Filter the mixture to remove the excess copper(II) oxide powder.<br /></div></li><li><div style='text-align: justify'>Transfer the filtrate to an evaporating dish and heat the solution until saturated.<br /></div></li></ol><p style='text-align: justify'>(To ensure the solution is saturated, dip a glass rod into the solution and take out. If there are crystals formed at the glass rod, this shows that the solution is saturated)<br /></p><ol><li><div style='text-align: justify'> Cool the saturated solution to room temperature.<br /></div></li><li><div style='text-align: justify'>Filter the salt crystals formed and dry the salt with filter paper.<br /></div></li></ol><p style='text-align: justify'> <br /> </p><p style='text-align: justify'><br /> </p><ol><li><div style='text-align: justify'>Chemical equation: CuO + H<sub>2</sub>SO<sub>4</sub> → CuSO<sub>4</sub> + H<sub>2</sub>O<br /></div></li></ol><p style='text-align: justify'><br /> </p><p style='text-align: justify'>5. <strong>Preparation of insoluble salts.<br /></strong></p><p style='text-align: justify'>Insoluble salts can be prepared by the <strong>precipitation</strong> or the <strong>double decomposition</strong> method. The general equation:<br /></p><p style='text-align: justify'>Salt solution of <strong>X</strong> + Salt solution of <strong>Y</strong> → Insoluble salt <strong>XY</strong> + Salt solution<br /></p><p style='text-align: justify'>Example: <strong>Pb</strong>(NO<sub>3</sub>)<sub>2</sub> + 2Na<strong>Cl</strong> → <strong>PbCl<sub>2</sub></strong> + 2NaNO<sub>3</sub><br /> </p><p style='text-align: justify'> (White precipitate)<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Ionic equation: Pb<sup>2+</sup> + 2Cl<sup>-</sup> → PbCl<sub>2</sub><br /> </p><p style='text-align: justify'>Example:<strong> To prepare silver chloride salt (an insolube salt)<br /></strong></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Substances: silver nitrate solution, sodium chloride solution.<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Apparatus: beaker, glass rod, filter funnel, evaporating dish, filter paper.<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>Procedures:<br /></p><p style='text-align: justify'><br /> </p><ol><li><div style='text-align: justify'>(30 – 50) cm<sup>3</sup> of silver nitrate solution is poured into a beaker.<br /></div></li><li><div style='text-align: justify'>(30 – 50) cm<sup>3</sup> of sodium chloride solution is added into the beaker.<br /></div></li><li><div style='text-align: justify'>Stir the mixture.<br /></div></li><li><div style='text-align: justify'>Filter the white precipate formed.<br /></div></li><li><div style='text-align: justify'>Wash the residue (white precipitate) with distilled water.<br /></div></li><li><div style='text-align: justify'>Dry the white powder with filter paper.<br /></div></li><li><div style='text-align: justify'>Chemical equation: AgNO<sub>3</sub> + NaCl → AgCl + NaNO<sub>3</sub><br /> </div></li><li><div style='text-align: justify'>Ionic equation: Ag<sup>+</sup> + Cl<sup>-</sup> → AgCl<br /></div></li><li><div style='text-align: justify'>White salt of siver chloride formed.<br /></div></li></ol><p style='text-align: justify'>Tips: When you are required to prepare a salt, the first thing to do is to determine whether the salt to be prepared is soluble or insoluble. Then choose the suitable method to prepare the salt.<br /></p><p style='text-align: justify'><strong>6. Numerical Problems Related to Salts.<br /></strong></p><p style='text-align: justify'>Example: Excess zinc is added to 50 cm<sup>3</sup> of sulphuric acid solution 1.0 mol dm<sup>-3</sup> . <br /></p><p style='text-align: justify'>The chemical reaction is shown below:<br /></p><p style='text-align: justify'> Zn + H<sub>2</sub>SO<sub>4</sub> → ZnSO<sub>4</sub> + H<sub>2</sub>.<br /></p><p style='text-align: justify'>Calculate the mass of zinc sulphate salt formed from the reaction.<br /></p><p style='text-align: justify'> [ Relative atomic mass: O, 16, S, 32; Zn, 65;]<br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'> Solution: From the equation, 1 mol of H<sub>2</sub>SO<sub>4</sub> ≡ 1 mol of ZnSO<sub>4</sub><br /> </p><p style='text-align: justify'> Number of moles of H<sub>2</sub>SO<sub>4</sub> given = <span style='text-decoration:underline'>MV</span><br /> </p><p style='text-align: justify'> 1000 <br /></p><p style='text-align: justify'> = <span style='text-decoration:underline'>1.0 x 50</span><br /> </p><p style='text-align: justify'> 1000<br /></p><p style='text-align: justify'> = 0.05<br /></p><p style='text-align: justify'> Therefore, mass of ZnSO<sub>4</sub> = 0.05 x (65 + 32 + 4(16))<br /></p><p style='text-align: justify'> = 8.05 g<br /></p><p style='text-align: justify'><strong>Exercise<br /></strong></p><p style='text-align: justify'><strong>Objective Questions:<br /></strong></p><ol><li><div style='text-align: justify'>Which of the following salts is not soluble in water?<br /></div><p style='text-align: justify'>A Sodium carbonate<br /></p><p style='text-align: justify'>B Silver nitrate<br /></p><p style='text-align: justify'>C Lead(II) chloride<br /></p><p style='text-align: justify'>D Zinc sulphate<br /></p></li><li><div style='text-align: justify'>Which of the following equations is <strong>correct</strong> for the preparation of copper(II) sulphate?<br /></div><p style='text-align: justify'>A Cu(NO<sub>3</sub>)<sub>2</sub> + Na<sub>2</sub>SO<sub>4</sub> → CuSO<sub>4</sub> + 2 NaNO<sub>3<br /></sub></p><p style='text-align: justify'>B Cu(OH)<sub>2</sub> + H<sub>2</sub>SO<sub>4</sub> → CuSO<sub>4</sub> + 2H<sub>2</sub>O<br /></p><p style='text-align: justify'>C Cu + H<sub>2</sub>SO<sub>4</sub> → CuSO<sub>4</sub> + H<sub>2</sub><br /> </p><p style='text-align: justify'>D CuCO<sub>3</sub> + H<sub>2</sub>SO<sub>4</sub> → CuSO<sub>4</sub> + H<sub>2</sub>O + CO<sub>2</sub><br /> </p></li><li><div style='text-align: justify'>When substance X is heated strongly, a type of gas and a black deposit were produced. The gas released turns lime water chalky. Which of the following is substance X?<br /></div><p style='text-align: justify'>A Copper(II) oxide<br /></p><p style='text-align: justify'>B Lead(II) carbonate<br /></p><p style='text-align: justify'>C Copper(II) carbonate<br /></p><p style='text-align: justify'>D Zinc carbonate<br /></p></li><li><div style='text-align: justify'>Which of the following nitrates will <strong>not</strong> releases brown gas when heated strongly?<br /></div><p style='text-align: justify'>A sodium nitrate<br /></p><p style='text-align: justify'>B magnesium nitrate<br /></p><p style='text-align: justify'>C lead(II) nitrate<br /></p><p style='text-align: justify'>D zinc nitrate<br /></p></li><li><div style='text-align: justify'>What will happen if an aqueous solution of sodium chloride is added to an aqueous solution of lead(II) nitrate?<br /></div><p style='text-align: justify'>I The solution becomes acidic<br /></p><p style='text-align: justify'>II Bubbles formed<br /></p><p style='text-align: justify'>III Neutralisation reaction occurs<br /></p><p style='text-align: justify'>IV White precipitate formed<br /></p><p style='text-align: justify'>A I, II and III<br /></p><p style='text-align: justify'>B I and II<br /></p><p style='text-align: justify'>C II and IV <br /></p><p style='text-align: justify'>D IV only<br /></p></li></ol><p style='text-align: justify'><strong>Structured Question</strong>.<br /></p><p style='text-align: justify'>The figure below shows some chemical reactions on X carbonate. <br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'> X carbonate Solution Y + H<sub>2</sub>O + Gas Z <br /></p><p style='text-align: justify'><br /> </p><p style='text-align: justify'>X carbonate is a green coloured powder. When added with acid R, blue coloured solution Y and gas Z that turns lime water chalky are produced.<br /></p><p style='text-align: justify'>(a) (i) Name one acid that could be R.<br /></p><p style='text-align: justify; margin-left: 18pt'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[1 mark]<br /></p><ol style='margin-left: 54pt'><li><div style='text-align: justify'>Name solution X when acid in (a)(i) is used.<br /></div></li></ol><p style='text-align: justify'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[1 mark]<br /></p><p style='text-align: justify; margin-left: 18pt'>(ii) Name gas Z.<br /></p><p style='text-align: justify; margin-left: 18pt'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[1 mark]<br /></p><p style='text-align: justify'>(b) X carbonate when heated strongly will also produce gas Z and a black deposit.<br /></p><p style='text-align: justify'>(i) Draw the apparatus set-up how the experiment can be carried out in the laboratory. Show also in your diagram how the gas can be tested.<br /></p><p style='text-align: right'> [3 marks<br /></p><p style='text-align: justify; margin-left: 18pt'>(ii) Write the chemical equation for the heating of X carbonate.<br /></p><p style='text-align: justify; margin-left: 18pt'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[1 marks]<br /></p><p style='text-align: justify; margin-left: 18pt'>(c) You are required to prepare X carbonate salt in the laboratory.<br /></p><p style='text-align: justify; margin-left: 18pt'>(i) Name the two substances that are required to prepare the salt.<br /></p><p style='text-align: justify; margin-left: 18pt'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[2 marks]<br /></p><p style='text-align: justify; margin-left: 18pt'>(ii) Name the type of reaction for the preparation of the salt above.<br /></p><p style='text-align: justify; margin-left: 18pt'>…………………………………………………………………………………………..<br /></p><p style='text-align: right; margin-left: 18pt'>[1 mark]<br /></p><p style='text-align: justify; margin-left: 18pt'>Answers:<br /></p><p style='text-align: justify; margin-left: 18pt'>Objective Questions.<br /></p><p style='text-align: justify; margin-left: 18pt'>1. C 2. D 3. C 4. A 5. D<br /></p><p style='text-align: justify; margin-left: 18pt'>Structured Questions<br /></p><ol><li><div style='text-align: justify'>(i) sulphuric acid<br /></div><p style='text-align: justify'>(ii) copper(II) sulphate<br /></p><ol><li><div style='text-align: justify'>carbon dioxide<br /></div></li></ol></li></ol><p style='text-align: justify'>(b)(i)<br /></p><p style='text-align: justify'> <br /> </p><p style='text-align: justify'> (ii) CuCO<sub>3</sub> → CuO + CO<sub>2</sub><br /> </p><p style='text-align: justify; margin-left: 18pt'>(c)(i) Copper(II) nitrate and sodium carbonate<br /></p><p style='text-align: justify; margin-left: 18pt'> (ii) precipitation/ double decomposition method.</p></span>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0tag:blogger.com,1999:blog-5815576565912281431.post-57957537442908045362011-05-03T06:23:00.000-07:002011-05-03T06:23:32.789-07:00Mid Year Exam 2011<div style="text-align: center;"><span style="color: #cc0000; font-family: Verdana, sans-serif; font-size: large;">Good luck to all my students in 5 Bestari, 5 Wawasan, 4 Cita and 4 Maju. </span></div>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com1tag:blogger.com,1999:blog-5815576565912281431.post-57977340223538188592011-05-03T06:06:00.000-07:002011-05-03T06:06:42.841-07:00Alkali Metal + H2O<div style="text-align: center;"><br />
This shows how reactive Group 1 Alkali Metals when they react with water</div><br />
<center><iframe allowfullscreen="" frameborder="0" height="349" src="http://www.youtube.com/embed/m55kgyApYrY" width="560"></iframe><center> </center><center> </center><center>What are the factor that contribute to this kind of reactivity??</center><center> </center><center>Why does the reactivity of Group 1 Metals increases as you go down the Periodic Table of Elements?</center><center> </center><center>*Try Answer It*</center></center>Norini Jaafarhttp://www.blogger.com/profile/17369740724890005066noreply@blogger.com0