Six-mark questions
Six-mark questions will only appear in the Depth paper. There will be two six-mark questions in the Depth paper.
Six-mark questions are extended free response questions, needing the longest answers. It is wise to plan your answer rather than rushing straight into it. Without a plan it is easy to stray away from the key points and lose marks, get steps in a process in the wrong order or forget key bits of information.
To gain six marks, you will need to:
- use appropriate scientific words and terms
- write your answer in full sentences, not bullet points
- write clearly, linking ideas in a logical way
- use and maintain a line of reasoning, rather than a random list of statements and sentences
- support explanations using scientific knowledge and understanding
Six-mark questions are marked using a levels-based mark scheme. An answer that is not clear and logically sequenced, and which does not give an argument supported by evidence, will be limited to the lower levels. Similarly, if the question asks you to discuss both sides of an argument, or explain two observations, you will be limited to the lowest level if your answer only considers one of them.
The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks, but you do need to write in full sentences, linking them logically and clearly.
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Writing six-mark answers with Dr Alex Lathbridge
Listen to the full series on 大象传媒 Sounds.
How to write six-mark answers in your science GCSE exams.
Sample question 1 - Foundation
Question
Suggest a practical method to investigate the reaction between zinc and hydrochloric acid.
The method should produce results that are as accurate as possible.
You should include alternative methods in your answer to help justify your choice. [6 marks]
Level 3 [5 to 6 marks]
To get the top marks, your answer needs to:
- compare three different methods for investigating rate of reaction, for example:
- loss of mass
- measuring volume with a gas syringe
- measuring volume with an inverted measuring cylinder in water
- evaluate the accuracy of results from each, for example:
- as the gas produced is hydrogen, the losses of mass will be very small so unless a very accurate balance is available this is not a good method
- The graduations on a gas syringe are more accurate than those on a measuring cylinder so this will produce less uncertainty in the measurements
- Present a well-developed line of reasoning which is clear and logically structured. The information presented is relevant and substantiated.
Level 2 [3 to 4 marks]
Your answer:
- compares two different methods and provides some comparison between the two in terms of accuracy of measurements
- provides is a line of reasoning presented with some structure
- provides relevant information presented and supported by some evidence
Level 1 [1 to 2 marks]
Your answer:
- describes a method to investigate rate of reaction but with little or no justification of why this method is preferable
- provides basic information communicated in an unstructured way
- provides information supported by limited evidence and the relationship to the evidence may not be clear
Sample question 2 - Higher
Question
The aim of the Haber process is to produce ammonia, but the reaction is reversible.
N2(g) + 3H2(g) 鈬 2NH3(g)
The forwards reaction is exothermic.
The conditions used for the reaction are a temperature of 400掳C and a pressure of 200 atmospheres.
Explain why these conditions were chosen. [6 marks]
Level 3 [5 to 6 marks]
To get the top marks, your answer needs to:
- describe the effect of temperature on the rate of reaction:
- a higher temperature will produce a faster reaction which is beneficial for an industrial process
- describe the effect of temperature on the position of equilibrium:
- a higher temperature favours the reverse reaction which would reduce the yield
- explain that 400掳C is a compromise temperature that ensures a reasonable yield whilst keeping the rate of reaction as fast as acceptable
- explain that a catalyst is used to increase the rate of reaction further
- describe the effect of pressure on the rate of reaction:
- a higher pressure will produce a faster reaction
- describe the effect of pressure on the position of equilibrium:
- a higher pressure favours the forwards reaction
- explain that increasing pressure is good in terms of increasing rate of reaction and improving yield but very high pressures a very expensive to achieve
- explain that 200 atmospheres is also a compromise as it balances an acceptable rate of reaction and yield with the cost of carrying out the reaction under pressure
- present a well-developed line of reasoning which is clear and logically structured, and in which the information presented is relevant and substantiated.
Level 2 [3 to 4 marks]
Your answer:
- fully explains either temperature or pressure, or correctly explains the effects of each on rate and position of equilibrium without discussion of how the final conditions are decided
- presents a line of reasoning with some structure
- presents relevant information supported by some evidence
Level 1 [1 to 2 marks]
Your answer:
- gives some correct explanations of the effect of temperature and pressure on rates of reaction or equilibrium position but no attempt to explain the actual reaction conditions
- provides basic information communicated in an unstructured way
- provides information supported by limited evidence and the relationship to the evidence may not be clear