Structured questions 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.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Sample question 1 - Foundation
Question
What is meant by the term 'activation energy'? [2 marks]
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
- The minimum energy (needed by particles)... [1]
- ...for a reaction to occur [1]
Sample question 2 - Foundation
Question
A student pours water into four polystyrene cups, and measures the temperature of the water.
She adds a different substance to each cup.
She stirs and measures the temperatures again.
Her results are in table 1.
Table 1
| Substance | Temperature of water at the start (°C) | Temperature of solution wen reaction finishes (°C) | Temperature change (°C) |
| copper sulfate | 20 | 26 | +6 |
| ammonium chloride | 20 | 15 | -5 |
| potassium nitrate | 20 | 11 | |
| calcium oxide | 20 | 31 |
| Substance | copper sulfate |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 26 |
| Temperature change (°C) | +6 |
| Substance | ammonium chloride |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 15 |
| Temperature change (°C) | -5 |
| Substance | potassium nitrate |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 11 |
| Temperature change (°C) |
| Substance | calcium oxide |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 31 |
| Temperature change (°C) |
a) Complete the table by writing in the missing values. [2 marks]
b) Write down the names of the two substances that dissolve in water exothermically. [1 mark]
a)
| Substance | Temperature of water at the start (°C) | Temperature of solution wen reaction finishes (°C) | Temperature change (°C) |
| copper sulfate | 20 | 26 | +6 |
| ammonium chloride | 20 | 15 | -5 |
| potassium nitrate | 20 | 11 | -9 [1 mark] |
| calcium oxide | 20 | 31 | +11 [1 mark] |
| Substance | copper sulfate |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 26 |
| Temperature change (°C) | +6 |
| Substance | ammonium chloride |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 15 |
| Temperature change (°C) | -5 |
| Substance | potassium nitrate |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 11 |
| Temperature change (°C) | -9 [1 mark] |
| Substance | calcium oxide |
|---|---|
| Temperature of water at the start (°C) | 20 |
| Temperature of solution wen reaction finishes (°C) | 31 |
| Temperature change (°C) | +11 [1 mark] |
b) Copper sulphate and calcium oxide. [1]
Sample question 3 - Higher
Question
Draw a reaction profile for an exothermic reaction using the axes provided below.
Show the:
- Relative energies of the reactants and products
- Activation energy and overall energy change
[2 marks]
Diagram should include:
- The correct relative energies of the reactants, products and the overall energy change labelled [1]
- The activation energy labelled [1]
Sample question 4 - Higher
Question
A teacher uses a teat pipette to place 1 cm3 of water on a block of wood.
She places a beaker on top of the water.
Then she mixes citric acid and sodium hydrogencarbonate in the beaker. When she stirs the mixture, there is a chemical reaction.
Suggest why the water under the beaker gets cold enough to freeze. Use the word exothermic or endothermic in your answer. [2 marks]
The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.
- The chemical reaction must be endothermic. [1]
- The reacting mixture takes in energy from the surroundings, including the water. [1]
