WM5

Question 1

Describe how you would carry out the recrystallisation in the laboratory to obtain a pure sample of acetaminophen

Answer 1

• Dissolve the sample in the minimum amount of hot ethanol
• filter off any impurities
• leave to form crystals
• filter off crystals
• wash and dry crystals

Question 2

Describe how the student would run the chromatography and analyse the chromatograph. Suggest any fritter action required to make aspirin

Answer 2

place plate in the beaker with solvent
solvent should be below the line of dots
allow solvent to rise through spots until solvent front is near the top
remove plate
dry plate
(state what each sample contains)
further purification is required
repeat chromatography after further crystallisation

Question 3

recrystallisation diagram

Answer 3

Question 4

chromatography diagram

Answer 4