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STOICHIOMETRY_PART_2

Total questions: 10

Worksheet time: 11mins

Name
Class
Date
1.

Diagram shows the chemical formula of potassium hexacyanoferrate(II) trihydrate.

What is the relative mass of this compound?

[Relative atomic mass : H =1; C= 12; N= 14; O= 16; K= 39; Fe = 56]

a)

141

b)

256

c)

389

d)

422

2.

What is the mass of phosphorus that contains twice the number of atoms found in 14 g of iron?

[Relative atomic mass : P = 31; Fe = 56]

a)

62.0 g

b)

28.0 g

c)

15.5 g

d)

10.7 g

3.

Gas jar X contains 10g of oxygen gas while gas jar Y contains 10g of chlorine gas.

Which of the following statements is true about chlorine and oxygen gas in gas jars X and Y?

a)

The number of gas molecules in both gas jars are the same.

b)

The distance between the molecules in gas jar Y is greater than that of gas jar X.

c)

Gas jar X contains greater number of moles of gas.

d)

The volumes of the two gases are the same.

4.

4.16 g of element W reacts with 1.92 g of oxygen to form metal oxide W. The empirical formula for this metal oxide is W2O3. What is the relative atomic mass of W?

[Relative atomic mass : O = 16]

a)

27

b)

52

c)

56

d)

104

5.

The following chemical equation shows the heating of hydrated magnesium sulphate.


MgSO4.7H2O (s) → MgSO4 (s) + 7H2O (g)


What is the number of moles of water vapour released when 54 g of magnesium sulphate is produced during the heating of hydrated magnesium sulphate?

[Relative atomic mass : Mg = 24; S = 32; O =16]

a)

0.45 mol

b)

3.15 mol

c)

4.50 mol

d)

6.30 mol

6.

Which of the following statements is true for one mole of a substance?

a)

1 mol of magnesium contains 6.02 × 1023 molecules

b)

1 mol of nitrogen gas contains 6.02 × 1023 atoms

c)

1 mol of water contains the same number of atoms as in 12 g of carbon-12

d)

1 mol of carbon dioxide contains the same number of molecules as the number of atoms in 12 g of carbon-12

7.

How many moles of ions are there in 1 mole of iron(III) oxide?

a)

2

b)

3

c)

5

d)

6

8.

0.58 g flavouring substance is used to improve the taste of a pineapple cake.

What is the number of molecules of the flavouring substance?

[Relative molecular mass of flavouring substance

= 116 gmol–1;

Avogadro constant = 6.02 × 1023 mol–1]

a)

1.20 × 1026

b)

3.01 × 1021

c)

3.32 × 10–22

d)

8.31 × 10–27

9.

The following equation represents the reaction between aluminium and oxygen.

4Al + 3O2 → 2Al2O3

Which of the following statements is correct?

a)

4 mol of aluminium atoms react with 3 mol of oxygen molecules

b)

4 mol of aluminium atoms react with 3 mol of oxygen atoms

c)

4 mol of aluminium atoms react with 3 mol of oxygen atoms producing 2 mol of aluminium oxide

d)

4 mol of aluminium atoms react with 6 mol of oxygen molecules producing 2 mol of aluminium oxide

10.

What is the number of atoms in 0.5 mol of ammonia gas? [Avogadro constant = 6.02 × 1023 mol–1]

a)

6.02 × 1023

b)

0.5 × 6.02 × 1023

c)

0.5 × 2 × 6.02 × 1023

d)

0.5 × 4 × 6.02 × 1023