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 an a level-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.
Writing six-mark answers with Dr Alex Lathbridge
Listen to the full series on BBC Sounds.
How to write six-mark answers in your science GCSE exams.
Sample question 1 - Foundation
Question
Eve works in a laboratory where food dyes are tested. Some dyes are banned because they are known to be harmful. Eve tests a jelly that will be exported to the USA using 0.2% sodium chloride solution as the solvent.
Below is a table of the Rf values of dyes banned in the USA.
| Food dye | Rf value in 0.2% sodium chloride solvent |
| Yellow 5 | 0.71 |
| Blue 2 | 0.37 |
| Yellow 6 | 0.52 |
| Red 3 | 0.10 |
| Food dye | Yellow 5 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.71 |
| Food dye | Blue 2 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.37 |
| Food dye | Yellow 6 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.52 |
| Food dye | Red 3 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.10 |
Eve's finished chromatogram is shown below.
Explain the conclusions Eve can make about the jelly. Include what she could do to increase the confidence in her conclusions. [6 marks]
OCR 21st Century Science, GCE Chemistry, Paper J258, 2015.
Level 3 [5 to 6 marks]
To get the top marks, your answer needs to:
- show correct understanding of output of the chromatogram and calculate correctly the Rf of some of the spots, including linking the Rf values to the table of food dyes
- answer calculates Rf of dyes (0.37/0.92) and compares spots with table
- make correct conclusions about the jelly
- one spot possibly a safe dye and one spot is a banned dye so it cannot be exported to the USA
- suggest improvements to increase confidence in the result
- use a different solvent
- suggest a different method
- look at a more extensive Rf table to identify the other dyes and check for safety
- provide 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]
The answer:
- shows correct understanding of the output of the chromatogram and calculates correctly the Rf of some of the spots, including linking the Rf values to the table
- makes some conclusions about the jelly or suggests improvements
- presents a line of reasoning presented with some structure
- presents relevant information supported by some evidence
Level 1 [1 to 2 marks]
The answer:
- shows correct understanding of the output of the chromatogram and attempts to calculate the Rf of a spot but does so incorrectly (though shows knowledge of the formula)
- 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
Eve works in a laboratory where food dyes are tested. Some dyes are banned because they are known to be harmful. Eve tests a jelly that will be exported to the USA using 0.2% sodium chloride solution as the solvent.
Below is a table of the Rf values of dyes. The first four are banned in the USA.
| Food dye | Rf value in 0.2% sodium chloride solvent |
| Yellow 5 | 0.71 |
| Blue 2 | 0.37 |
| Yellow 6 | 0.52 |
| Red 3 | 0.10 |
| Red 40 | 0.25 |
| Blue 1 | 0.88 |
| Food dye | Yellow 5 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.71 |
| Food dye | Blue 2 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.37 |
| Food dye | Yellow 6 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.52 |
| Food dye | Red 3 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.10 |
| Food dye | Red 40 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.25 |
| Food dye | Blue 1 |
|---|---|
| Rf value in 0.2% sodium chloride solvent | 0.88 |
Eve's finished chromatogram is shown below.
Explain the conclusions Eve can make about the jelly. Include what she could do to increase the confidence in her conclusions. [6 marks]
OCR 21st Century Science, GCE Chemistry, Paper J258, 2016 - Higher.
Level 3 [5 to 6 marks]
To get the top marks your answer needs to:
- show correct understanding of output of the chromatogram and calculate correctly the Rf of some of the spots, including linking the Rf values to the table of food dyes leading to identification issues
- answer calculates Rf of dyes (0.22/0.25/0.88) and compares with table.
- notices that two spots have very close Rf values and have merged into one spots and comments on difficulty of calculating Rf value.
- make correct conclusions about the jelly
- not a clear result
- one spot possibly a safe dye
- possibly two banned dyes
- cannot be exported to the USA
- suggest improvements to increase confidence in the result
- use a different solvent
- suggest a different method
- provide a well-developed line of reasoning which is clear and logically structured, with information presented that is relevant and substantiated
Level 2 [3 to 4 marks]
The answer:
- shows correct understanding of the output of the chromatogram and calculates correctly the Rf of some of the spots, including linking the Rf values to the table
- makes some conclusions about the jelly or suggests improvements
- presents a line of reasoning presented with some structure
- presents relevant information supported by some evidence
Level 1 [1 to 2 marks]
The answer:
- shows correct understanding of the output of the chromatogram and attempts to calculate the Rf of a spot but does so incorrectly (though shows knowledge of the formula)
- provides basic information communicated in an unstructured way
- provides information supported by limited evidence and the relationship to the evidence may not be clear
