Formulae, Functional Groups & Terminology | CIE IGCSE Chemistry: Co-ordinated Sciences (Double Award) Exam Questions 2023

11 mark

The diagrams show part of the structures of five substances, A, B, C, D and E.

dFPHIipH_q1-0620_s19_qp_32

Which one of these structures, A, B, C, D or E is an alcohol?

How did you do?

Did this page help you?

5a2 marks

Petrol is a mixture of hydrocarbons and additives. The combustion of petrol in car engines is a major source of air pollution. This is reduced by catalytic converters.

Petrol is obtained from the gasoline fraction, boiling point range 40 °C to 100 °C, from the distillation of petroleum.

Explain the term fraction.

How did you do?

5b6 marks

Extended tier only

In many countries, a lead compound of the type Pb(C₂H₅)_n used to be added to petrol to improve its combustion. After combustion, lead oxide was formed.

i)

Octane is a constituent of petrol. Write the equation for the complete combustion of octane.

C₈H₁₈ + .......... O₂ → .......... + ..........

[2]

ii)

Dibromoethane was added to petrol to remove the lead oxide from inside the engine. Lead bromide was formed which escaped into the environment through the exhaust. Leaded petrol cannot be used with a catalytic converter.

Give another reason why leaded petrol is no longer used.

[1]

iii)

What does each of the following tell you about the structure of dibromoethane?

dibromo ......................................................................................................................

eth ..............................................................................................................................

ane .......................................................................................................................

[2]

iv)

What additional information is needed to draw the structural formula of dibromoethane?

[1]

How did you do?

5c2 marks

Extended tier only

An analysis of the compound, Pb(C₂H₅)_n, showed that 0.026 moles of Pb was combined with 0.104 moles of C₂H₅ groups.

What is the value of n? Show how you arrived at your answer.

How did you do?

5d3 marks

Extended tier only

Some of the pollutants emitted by vehicle exhausts are carbon monoxide, oxides of nitrogen and unburnt hydrocarbons. Explain how the emission of these gases is reduced by a catalytic converter.

How did you do?

Did this page help you?

alcohol	formula	heat of combustion in kJ / mol
methanol	CH₃OH	730
ethanol	CH₃–CH₂–OH	1380
propan-1-ol
butan-1-ol	CH₃–CH₂–CH₂–CH₂–OH	2680
pentan-1-ol	CH₃–CH₂–CH₂–CH₂–CH₂–OH	3350

formula	$C_{2} H_{2}$	$C_{3} H_{4}$
structure		$H - C \equiv C - {CH}_{3}$	$H - C \equiv C - {CH}_{2} - {CH}_{3}$
names	ethyne		but-1-yne

	2C₄H₁₀ (g)	+ 13O₂ (g)	→ 8CO₂ (g)	+ 10H₂O (g)
volume of gas / cm³	..........	..........	40

Formulae, Functional Groups & Terminology (CIE IGCSE Chemistry: Co-ordinated Sciences (Double Award))

Exam Questions

Separate: Chemistry Only