Edexcel IGCSE Chemistry 1.13 Paper chromatography practical
Practise setting up paper chromatography investigations and explaining how apparatus choices affect valid dye results.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
Exam points
- describe placing pencil baseline spots above the solvent in a beaker or chromatography tank
- explain why pencil is used and why ink or submerged spots would contaminate results
- compare experiments fairly by keeping the solvent and chromatography paper the same
1.13 Paper chromatography practical question 1
[Maximum number: 6]
A student uses paper chromatography to investigate the dyes in five different inks, V, W, X, Y and Z.
This is what she uses.
- a beaker
- a piece of chromatography paper with a pencil line drawn near the bottom of the paper
- a solvent
- inks V, W, X, Y and Z
Question (a)
(a)
Describe how the student should set up and carry out her experiment.
You may draw a diagram to help with your answer.
[ 4 ]
- put separate spots of each ink on the pencil line
- pour some solvent into the bottom of the beaker
- place the paper in the beaker so that the spots are just above the solvent level
- leave until the solvent has risen near the top of the paper, then take the paper out
Accept:
- water for solvent throughout
- leave until the inks have stopped separating / spots or dyes stopped moving
Marking guidance:
- If a diagram shows solvent above the pencil line, only M1 and M2 can score.
- Do not award M3 if words and diagram contradict each other.
- Ignore references to leaving for a specified length of time.
Question (b)
(b)
Explain why the line on the paper is drawn in pencil rather than in ink.
[ 2 ]
- ink would / might dissolve in the solvent, or pencil would not dissolve in the solvent
- ink would interfere with / contaminate the results, or pencil would not interfere with / contaminate the results
Accept:
- water for solvent
- ink would produce spots / other colours / get mixed up with inks / move up the paper
- pencil would not produce spots / other colours / get mixed up with the inks / move up the paper
Ignore:
- smudge / run
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