Structured questions

This is the most common question on exam papers, although the number of marks for each question may vary.

At its simplest, this type of question will ask you to remember a simple fact that you have been taught. This type of question is likely to be worth one mark, and will often start with 'Give...', 'State...' or 'Name..'. In some cases, a question may ask you to state two things, rather than just one, and will be worth 2 marks.

Other structured questions may be worth two or more marks. These will often start with a command word such as 'Describe...' or 'Explain...', and will require a more detailed answer:

  • if you are asked to describe something, you need to give an account but no reason
  • if you are asked to explain something, you must give reasons or explanations

More complex structured questions will be worth three or four marks. They include questions with complex descriptions and explanations, questions in which you need to compare and contrast two different things or calculations with several stages.

The mark schemes given here may show answers as bullet points. This is to show clearly how a mark can be obtained. However, it is important that your answer is written in a logical, linked way. Examiners will not credit a key word if it is used out of context, or if your answer contradicts itself.

Sample question 1 - Foundation

Question

An oil company separates crude oil into the fractions listed below.

AC1 to C4
BC5 to C8
CC9 to C12
DC13 to C16
EC17 to C20
FC21 to C24
GC25 to C28

a) Write down the letter of the fraction with the biggest molecules. [1 mark]

b) Write down the letter of one fraction that boils at higher temperatures than fraction D. [1 mark]

c) Write down the letter of the one fraction that leaves the very top of a fractionating column. [1 mark]

d) Write down the chemical formula of the compound in fraction A whose molecules have one carbon atom joined to four hydrogen atoms. [1 mark]

Question courtesy of Eduqas.

a) G [1]

b) E/F/G [1]

c) A [1]

d) CH4 [1]

Sample question 2 - Foundation

Question

Methane is a hydrocarbon. It burns completely in oxygen to make carbon dioxide and water.

a) Write a word equation for the burning reaction of methane. [1 mark]

b) Write a balanced symbol equation for the burning reaction of methane, including state symbols. Use these formulae: CH4, O2, CO2, H2O [3 marks]

This question has been written by a Bitesize consultant as a suggestion to the type of question that may appear in an exam paper.

a) methane + oxygen → carbon dioxide + water [1]

b) CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)/(g)

  • correct reactants and products [1]
  • correct balancing numbers [1]
  • correct state symbols [1]

Sample question 3 - Higher

Question

Crude oil is a mixture of hydrocarbons.

a) Describe briefly how crude oil was formed. [2 marks]

b) Explain how crude oil is separated into different fractions. [4 marks]

Question courtesy of Eduqas.

Award [2] for any four of the following points; award [1] for any two:

a)

  • formed from the remains of marine life/remains of sea animals and plants
  • buried/compacted under sediment (over time)
  • no oxygen
  • change chemically/turn to oil under heat and pressure
  • over millions of years

[2]

b)

  • crude oil is heated until it boils/evaporates [1]
  • compounds with longer chain lengths have higher boiling points/shorter chain lengths have lower boiling points [1]
  • higher the boiling point the lower down the column the compounds condense [1]
  • compounds with similar chain lengths condense at similar temperatures and are collected as part of the same fraction [1]

Sample question 4 - Higher

Question

The table below shows the relative amounts of 'supply' and 'demand' for some hydrocarbon fractions.

Hydrocarbon fractionSupplyDemand
C1-C41%5%
C5-C812%28%
C9-C127%21%
C13-C1615%25%
C17-C2034%14%
C21-C2420%5%
C25-C2810%2%

Explain how oil companies process crude oil to address the differences in supply and demand of each fraction. [3 marks]

Question courtesy of Eduqas.

Process of cracking used [1] which involves breaking larger molecules into smaller molecules. [1]

Since demand for the C17 to C20/C21 to C24/C25 to C28 fraction is greater than supply, cracking this fraction produces smaller molecules for which demand exceeds supply. [1]