chapter 4

1.What is the relative molecular mass of carbon dioxide, C0₂? The relative

atomic masses of carbon and oxygen are 12 and 16, respectively.

• 44

• 44 amu

• 12

• 16

2. Calculate the relative molecular mass of glucose, C₆H₁₂0₆·

(Relative atomic masses: H = 1, C = 12 and 0 = 16)

• 180 amu

• 12

• 16

• 180

A compound of carbon and hydrogen contains 85.7 %of carbon and 14.3 %

of hydrogen by mass. Deduce the empirical formula of this hydrocarbon. {H = l, C = 12)

• C₂H₂

• CH₂

• CH

• CH₄

A compound has the empirical formula CH₂Br. Its relative molecular mass is 188.

Deduce the molecular formula of this compound. (Br == 80, C = 12. H = l)

• C₂H₄Br₂

• C₁H₂Br₂

• C₁H₂Br

• C₁H₂Br₂

The empirical formula of octane (C₈H₁₈) is -----.

• C2H6

• C16H36

• C8H16

• (d) C4H9

The formula of magnesium sulphate is ---------.

• MgSO₄

• Mg₂SO₄

• MgSO

• MgS

the empirical formulae for hydrazine, N₂H₄

• N₁H₂

• NH

• NH₂

• N₂H₂

the formula of

potassium carbonate,

• K₂CO₃

• KCO₃

• K₂CO

• K₃CO₃

the formula of

potassium hydrogen carbonate,

• K₂HCO₃

• K₂CO₃

• KCO₃

• KHCO₃

the formula of sulphur trioxide

• SO₂

• SO₃

• S₂O₂

• SO