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, the points are linked to each other, and are relevant to the question.
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
Place a tick (✔) in one box in each row of the table to show the best method to separate the first named substance from each of the mixtures. [3 marks]
| Substance | Crystallisation | Filtration | Simple distillation | Fractional distillation |
| Sand from a mixture of sand and sodium chloride solution | ||||
| Copper sulfate crystals from copper sulfate solution | ||||
| Useful liquids from crude oil |
| Substance | Sand from a mixture of sand and sodium chloride solution |
|---|---|
| Crystallisation | |
| Filtration | |
| Simple distillation | |
| Fractional distillation |
| Substance | Copper sulfate crystals from copper sulfate solution |
|---|---|
| Crystallisation | |
| Filtration | |
| Simple distillation | |
| Fractional distillation |
| Substance | Useful liquids from crude oil |
|---|---|
| Crystallisation | |
| Filtration | |
| Simple distillation | |
| Fractional distillation |
Edexcel question courtesy of Pearson Education Ltd.
| Substance | Crystallisation | Filtration | Simple distillation | Fractional distillation |
| Sand from a mixture of sand and sodium chloride solution | ✔ | |||
| Copper sulfate crystals from copper sulfate solution | ✔ | |||
| Useful liquids from crude oil | ✔ |
| Substance | Sand from a mixture of sand and sodium chloride solution |
|---|---|
| Crystallisation | |
| Filtration | ✔ |
| Simple distillation | |
| Fractional distillation |
| Substance | Copper sulfate crystals from copper sulfate solution |
|---|---|
| Crystallisation | ✔ |
| Filtration | |
| Simple distillation | |
| Fractional distillation |
| Substance | Useful liquids from crude oil |
|---|---|
| Crystallisation | |
| Filtration | |
| Simple distillation | |
| Fractional distillation | ✔ |
Sample question 2 - Foundation
Question
A student carries out an experiment to determine the melting point of a waxy solid. She heats a sample until it melts, then measures and records its temperature as it cools down.
Explain how the student could use her results to decide whether the waxy solid is a pure substance or a mixture. [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.
- Plot a graph of temperature against time. [1]
- Temperature should stay the same at the melting point/freezing point. [1]
- A pure substance gives a sharp melting point/freezing point (line should be horizontal). [1]
- A mixture melts over a range of temperatures (line will not be horizontal). [1]
Sample question 3 - Higher
Question
Explain why a mixture of ethanol and water can be separated using fractional distillation. [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.
- Ethanol and water have different boiling points. [1]
- Ethanol evaporates more easily when heated. [1]
- The first fractions will contain more (or, a higher concentration of) ethanol. [1]
Sample question 4 - Higher
Question
Describe the three of the main stages in treating fresh water to make it potable. [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.
- One of the following: screening to remove large objects, or coarse filter to remove grit particles, or fine filter to remove very small particles. [1]
- Sedimentation (using aluminium sulfate to clump smaller insoluble particles together), to settle particles to the bottom. [1]
- Chlorine to kill harmful microorganisms/germs. [1]
