## Tuesday, 12 July 2011

### Homework for the weekend

TOPIK: CHEMICAL FORMULAE AND
EQUATION

1. The equation below represents the   reaction to extract aluminium from aluminium oxide.
2Al3O3    4Al  +  3O2

What is the mass of aluminium that can be extracted from 102 g of  aluminium oxide?
[Relative atomic mass: O, 16 ; Al, 27]
1. 13.5 g                          C.  54.0 g
2. 27.0 g                          D.  108.0 g
4.          XCO3       XO  +  CO2

The equation above shows the action of heat on the carbonate salt of metal X.
How many moles of XCO3 are needed to produce 4.0 g of oxide X?
[Relative atomic mass: C, 12; O, 16; X, 64]
1. 0.03                             C.  0.08
2. 0.05                             D.  0.09

5.. What is the number of molecules in 1  mole of ammonia, NH3?
[Avogadro’s constant: 6.0 x 1023 mol-1]
A.    1.5 x 1023 molecules
B.     6.0 x 1023 molecules
C.    1.2 x 1024 molecules
D.    2.4 x 1024 molecules

6. A compound with the formula X2CO3 has a relative formula mass of 138.
What is the relative atomic mass of X?
[Relative atomic mass: C=12, O=16]
1. 39                                C.  78
2. 69                                D.  110

7. The table shows the mass of elements M  and O in an oxide, and the relative  atomic mass  of elements M and O.

 Element M O Mass/g 5.6 2.4 Relative atomic mass 56 16

The empirical formula for oxide M is
1. M2O3                           C.  MO2
2. M2O                            D.  MO
8. 5 g of element X reacted with 8  of element Y to form a compound with the formula XY2
What is the relative atomic mass of element X?
[Relative atomic mass of Y=80]
A.    25                                C.  50
B.     40                                D.  100

9. Which of the following statement is true for one mole of a substance?
A.    1 mol of copper contains 6.02 x 1023 molecules
B.     1 mol of oxygen gas contains 6.02 x 1023 atoms
C.    1 mol of water contains the same number of atoms as in 12g of carbon-12
D.    1 mol of carbon dioxide contains the same number of molecules as the number of atoms in 12g of carbon-12

10. Table below shows two elements and their respective relative atomic mass.
The letters used are not the actual symbol of  the elements.
 Element Relative atomic mass X 24 M 12

Which of  the following is true about the atoms of elements X and M?
A.    The mass of 1 mol of X is twice the mass of 1 mol of M
B.     1 mol of X has the same mass as 1 mol of M
C.       The mass of an atom of X is 24 g and the mass of an atom of M is 12 g
D.     The number of mole in 12 g of atom X is equal to the number of mole in 12 g of atom M.
11. A balloon contains 6.02 x 1023 of gas particles. What is the number of moles
of the gas in the balloon?
A  0.5 mol               C  3.0 mol
B  1.0 mol               D  6.0 mol

12. One mole of a substance is defined as the quantity of a substance that contains the same number of particles in m g of element Y.  What are m and Y?
 m Y A 2 Hydrogen - 1 B 12 Carbon - 12 C 14 Nitrogen - 14 D 16 Oxygen - 16

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?
[Relative atomic mass:O,16; M,56]
A MO                     C M2O
B MO2                    D M2O3

14. Which of the following gases contains 0.4 mol of atoms at room temperature and pressure?
[1 mol of gas occupies the volume of 24 dm3at room temperature and pressure]
A  4.8 dm3 He       C  4.8 dm3 SO3
B  4.8 dm3 H2        D  4.8 dm3 CO2

15. The following equation shows the decomposition reaction of copper(II) carbonate when heated at room temperature and pressure.
CuCO3    CuO  +  CO2
Which of the following is not true when 1 mol of copper(II) carbonate is decomposed?
[Relative atomic mass: C = 12, O=16, Cu = 64 and 1 mol of gas occupies the volume of 24 dm3 at room temperature and pressure.]
A 1 mol of copper(II) oxide is formed
B 1 molecule of carbon dioxide gas is
given off
C 80 g of copper(II) oxide is formed
D 24 dm3 of carbon dioxide gas is given off

16. Which of the following contains 6.02 x 1023 atoms?
A 1 mol of nitrogen gas
B 1 mol of chlorine gas
C 1 mol of ammonia gas
D 1 mol of neon gas

17. What is the number of moles of copper(II) nitrates in 56.4 g of copper(II) nitrate, Cu(NO3)2?
[Relative atomic mass: O=16, Cu=64, N=14]
A  0.30 mol             C  0.45 mol
B  0.32 mol             D  3.33 mol

18. Sodium reacts with chlorine to form sodium chloride.
2Na  +  Cl2    2NaCl

19.  What is the mass of sodium chloride formed when 2.30 g of sodium reacts with excess chlorine?
[Relative atomic mass: Na=23, Cl=35.5]
A 2.93g           C 9.40g
B 5.85g           D 11.70g

20. The relative molecular mass of M2(SO4)3 is 342. What is the relative atomic mass of element M?
[Relative atomic mass: O=16, S=32]
A 27                C 118
B 53                D 123

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?
[Relative atomic mass: O=16, Fe=56]
A Fe2O3           C FeO2
B Fe3O4           D FeO

22. What is the minimum mass of zinc required to react with excess hydrochloric acid to produce 240 cm3 of hydrogen gas at room conditions?
[Molar volume of gas = 24 dm3 mol-1 at room conditions;
Relative atomic mass: Zn = 65]
A 0.33 g          C 1.30 g
B 0.65 g          D 6.50 g

END OF QUESTIONS
THANK YOU
STEP UP YOUR EFFORTS TO ACHIEVE EXCELLENT RESULTS

#### 1 comment:

1. thank you puan for being such a dedicated person!