Structured and short answer questions
Questions with 1, 2, 3 or 4 marks usually start with command words. If a question starts with the command word 'state', 'give', 'name' or 'write down', it needs a short answer only. This type of question can often be answered with one word or phrase.
It is important to state, give, name or write down the number of things that the question asks for. If you write down fewer, you cannot get all the marks. If you write down more, and one is wrong, you might lose a mark.
Learn about command words with Dr Alex Lathbridge
Listen to the full series on BBC Sounds.
Understanding the different command words in your science GCSE exams.
Some questions start with the command words 'describe', 'explain' or 'compare'. These are often worth two or more marks:
- Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.
- Explain means you need to make something clear, or state the reasons for something happening. The points in the answer must be linked together. The answer must not be a list of reasons. All the points must be relevant to the question.
- Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.
More complex structured questions will be worth three or four marks. They include questions with complex descriptions and explanations, and questions in which you need to compare things.
Some of the answers are shown here as bullet points. This is to show clearly how a mark can be obtained. However, do not use bullet points in your answers - the points must be linked together logically.
Sample question 1 - Foundation
Question
A student heated some copper carbonate in a boiling tube.
The reaction shown by the equation below occurred.
CuCO3(s) → CuO(s) + CO2(g)
He measured the mass of the contents of the boiling tube before and after the reaction.
His results are in table 1.
Table 1
| When mass was measured | Mass of contents of crucible |
| Before the reaction | 2.48 g |
| After the reaction | 1.60 g |
| When mass was measured | Before the reaction |
|---|---|
| Mass of contents of crucible | 2.48 g |
| When mass was measured | After the reaction |
|---|---|
| Mass of contents of crucible | 1.60 g |
Explain the change in mass. [2 marks]
This question is AQA material which is reproduced by permission of AQA.
Mass decreased [1] because one of the products/carbon dioxide was formed as a gas that escaped into the air. [1]
Sample question 2 - Foundation
Question
A student heated some magnesium ribbon in a crucible with a lid.
The reaction shown by the equation below occurred.
2Mg(s) + O2(g) → 2MgO(s)
She measured the mass of the contents of the crucible before and after the reaction.
Her results are in table 2.
Table 2
| When mass was measured | Mass of contents of crucible |
| Before the reaction | 1.50 g |
| After the reaction | 2.30 g |
| When mass was measured | Before the reaction |
|---|---|
| Mass of contents of crucible | 1.50 g |
| When mass was measured | After the reaction |
|---|---|
| Mass of contents of crucible | 2.30 g |
Explain the change in mass. [2 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.
- The mass increased. [1]
- Because magnesium joined with oxygen/a gas from the air. [1]
Sample question 3 - Higher
Question
A student has a solution. The student knows:
- the mass of a solute in the solution
- the volume of the solution
- the mass of one mole of the solute
Explain how to find the concentration of the solution in mol/dm3. [2 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.
Calculate the concentration in g/dm3 by dividing the mass of the solute in g by the volume of solution in dm3. [1]
Then divide the concentration in g/dm3 by the mass of one mole of solute to find the concentration in mol/dm3. [1]
Sample question 4 - Higher
Question
A student wanted to make 10.0 g of zinc chloride.
The equation for the reaction is:
ZnO(aq) + 2HCl(aq) → ZnCl2(aq) + H2O(l)
Calculate the mass of zinc oxide the student needs to react with the dilute acid to make 10.0 g of zinc chloride. [4 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.
Mr of zinc chloride = 65 + (2 × 35.5) = 136 [1]
Amount of zinc chloride in mol = 10.0 g ÷ 136 g/mol
= 0.0735294 mol [1]
Amount of zinc oxide required = 0.0735294 mol
Mr of zinc oxide = 65 + 16 = 81 [1]
Mass of zinc oxide = 0.0735294 mol × 81 g/mol
= 6.0 g (2 significant figures) [1]
