Structured questions
Simple recall questions are usually worth one mark. They often have command words like 'give...', 'state...', 'name...' or 'identify...'. Some questions may ask you to state two things, rather than just one, and will be worth two marks.
Structured questions, with command words such as 'Describe...' or 'Explain...', will be worth two or more marks:
- 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 manner, giving points that are linked to each other and are relevant to the question.
Edexcel questions courtesy of Pearson Education Ltd.
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.
Sample question 1 - Foundation
Question
The fertiliser ammonium phosphate can be made by adding ammonia solution from a burette, to dilute phosphoric acid solution in a flask.
Describe what you would do to add the exact amount of ammonia solution needed to neutralise the acid solution.
[2 marks]
- Add an indicator (or name of suitable indicator) to the acid. [1]
- Add the ammonia solution until the indicator changes colour. [1]
Sample question 2 - Foundation
Question
State what is meant by the term electrolyte.
[2 marks]
- A substance that conducts electricity. [1]
- And one of the following points:
- when molten or in aqueous solution
- because it contains freely moving ions [1]
Sample question 3 - Higher
Question
The method used to prepare a salt depends on its solubility in water.
Complete the table by placing one tick in each row to show whether the salt is soluble or insoluble.
[2 marks]
| Salt | Soluble | Insoluble |
| Ammonium chloride | ||
| Lithium sulfate | ||
| Magnesium carbonate |
| Salt | Ammonium chloride |
|---|---|
| Soluble | |
| Insoluble |
| Salt | Lithium sulfate |
|---|---|
| Soluble | |
| Insoluble |
| Salt | Magnesium carbonate |
|---|---|
| Soluble | |
| Insoluble |
| Salt | Soluble | Insoluble |
| Ammonium chloride | ✔ | |
| Lithium sulfate | ✔ | |
| Magnesium carbonate | ✔ |
| Salt | Ammonium chloride |
|---|---|
| Soluble | ✔ |
| Insoluble |
| Salt | Lithium sulfate |
|---|---|
| Soluble | ✔ |
| Insoluble |
| Salt | Magnesium carbonate |
|---|---|
| Soluble | |
| Insoluble | ✔ |
All three correct. [2]
Any two correct. [1]
Sample question 4 - Higher
Question
When a solution of sodium sulfate, Na2SO4, is electrolysed, hydrogen gas is formed at one of the electrodes.
Explain how hydrogen can be formed at a particular electrode during this electrolysis.
[4 marks]
- H+ (hydrogen ions) ions come from (the break-up of water). [1]
- The hydrogen ions are attracted to the negative electrode. [1]
- At the electrode the ions are reduced (gain electrons). [1]
- The ions change into hydrogen atoms/molecules. [1]
Alternative to last two points: 2H+ + 2e- → H2 [2]
