The command words, and what each one is really asking for
| Command word | What it means | What that looks like in an exam answer |
|---|---|---|
| Assess | Make an informed judgement. | A judgement with support - not just an opinion. |
| Calculate | Work out from given facts, figures or information. | Show the working. A bare number with no method can lose the mark. |
| Comment | Give an informed opinion. | State your view, then back it with a reason from the topic. |
| Compare | Identify and comment on similarities and/or differences. | You must give both sides - describing only one caps your marks. |
| Contrast | Identify and comment on differences. | Differences only, but still both sides. |
| Define | Give precise meaning. | One precise sentence. Do not describe or give examples instead. |
| Describe | State the points of a topic, give characteristics and main features. | What it is and what it involves. No reasons required. |
| Determine | Establish an answer using the information available. | Use the data or information given, not recall. |
| Discuss | Write about the issue or topic in depth in a structured way. | Both sides, organised, with a conclusion. |
| Evaluate | Judge the quality, importance, amount or value of something. | Weigh it up and reach a supported judgement. No judgement, no top mark. |
| Explain | Set out purposes or reasons, make relationships clear, say why and/or how, and support with relevant evidence. | Every point needs a reason or consequence. This is where most marks are lost. |
| Give | Produce an answer from a given source, or recall from memory. | Short and direct. |
| Identify | Name, select or recognise. | Just the answer - no explanation needed. |
| Justify | Support a case with evidence or argument. | A claim plus the evidence that supports it. |
| Outline | Set out the main points. | Brief points, no development. |
| Predict | Suggest what may happen based on the information available. | Use the information given, not guesswork. |
| Show (that) | Provide structured evidence that leads to a given result. | Work through the steps so the result follows. |
| Sketch | Make a simple freehand drawing showing the key features, taking care over proportions. | Label it. Proportions matter more than artistic quality. |
| State | Express in clear terms. | One clear fact per mark. Do not waste time developing it. |
| Suggest | Apply knowledge and understanding to situations where there are a range of valid responses, in order to make proposals or put forward considerations. | Apply it to the situation given - that is what is being tested. |
Cambridge publishes these command words in the 9701 syllabus. At AS & A Level the marks usually sit in the equation you write, the state symbols, the unit, the mechanism and the reason - state the equation, calculate, deduce and explain are where most marks are won and lost.
The difference that matters most
Look at the same knowledge asked three ways. Same topic, three different answers, three different marks.
| Command | Question | Answer that scores full marks |
|---|---|---|
| State (1) | State the type of reaction that joins two amino acids together. | Condensation. |
| Explain (2) | Explain why the first ionisation energy of aluminium is lower than that of magnesium. | Aluminium's outermost electron is in a 3p orbital, which is higher in energy and further from the nucleus than the 3s orbital the magnesium electron is removed from (1); the 3p electron is also shielded by the full 3s subshell, so less energy is needed to remove it (1). |
| Calculate (3) | Calculate the volume of 0.100 mol dm-3 sodium hydroxide needed to neutralise 25.0 cm3 of 0.150 mol dm-3 hydrochloric acid. | Moles of HCl = 0.150 x 25.0 / 1000 = 3.75 x 10-3 mol (1); the equation shows a 1:1 ratio, so the same number of moles of NaOH is needed (1); volume = 3.75 x 10-3 / 0.100 = 0.0375 dm3 = 37.5 cm3 (1). |
Learn this pattern. Fact. Then consequence. Then the context. Almost every lost mark is a missing middle step.
Command-word trainer
Read the question, decide what the command word demands, write the answer, then compare it with the model answer.