TOPIK: CHEMICAL FORMULAE AND
1. The equation below represents the reaction to extract aluminium from aluminium oxide.
What is the mass of aluminium that can be extracted from 102 g of aluminium oxide?
[Relative atomic mass: O, 16 ; Al, 27]
- 13.5 g C. 54.0 g
- 27.0 g D. 108.0 g
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]
- 0.03 C. 0.08
- 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]
- 39 C. 78
- 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.
Relative atomic mass
The empirical formula for oxide M is
- M2O3 C. MO2
- 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.
Relative atomic mass
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?
Hydrogen - 1
Carbon - 12
Nitrogen - 14
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
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.
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
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