Paper chromatography
3 marks · EasyDescribe how you would carry out a paper chromatography experiment to determine if a black ink contains more than one dye. Include three steps in your description.
Step 1:
Step 2:
Step 3:
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Draw a pencil line near the bottom of the chromatography paper and place a spot of black ink on it.
(b) Suspend the paper in a beaker with a small amount of solvent, making sure the ink spot is above the solvent level.
(c) Remove the paper when the solvent front is near the top and observe the number of spots formed above the original ink spot.
Common mistakes: Using pen for the line; Adding ink below solvent
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Draws pencil line, puts black ink spot on line
B2 (b) · 1 mark · Suspends paper with spot just above solvent; ensures solvent is below the pencil line
B3 (c) · 1 mark · Removes paper when solvent front nears top, observes/sees number of spots formed (more than one spot => more than one dye)
Worked solution
1. Draw a pencil line near the bottom of the paper and place a small spot of black ink on the line. 2. Stand the paper in a beaker containing a small amount of solvent so the ink spot is above the solvent. 3. Allow the solvent front to move near the top, then remove the paper and observe if there are multiple spots above the original ink spot (indicating more than one dye).