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3.2 Methods of separating and purifying substances

3.2 Methods of separating and purifying substances

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Question 59

During an investigation into the catalytic decomposition of hydrogen peroxide, a student recovers the insoluble manganese dioxide catalyst from the reaction mixture at the end of the experiment.

To find the mass of the recovered catalyst, the student:

  1. Filters the reaction mixture containing the catalyst.
  2. Measures the mass of the wet filter paper and the catalyst.
  3. Subtracts the mass of a dry piece of filter paper of the same size.

This method does not give an accurate mass of the remaining catalyst.

Which of the following modifications to the method would give a more accurate mass?

A

Dry the filter paper and catalyst in an oven or desiccator before weighing them.

B

Scrape the wet catalyst off the filter paper and weigh it directly on the balance.

C

Measure the mass of the filtrate and subtract it from the starting mass of the solution.

D

Repeat the filtration process several times using the same wet filter paper.

Markscheme

3.2 Methods of separating and purifying substances Questions

  1. GCSE
  2. /Chemistry
  3. /3.2 Methods of separating and purifying substances

107 exam-style questions on Edexcel GCSE Chemistry 3.2 Methods of separating and purifying substances, covering 3.2.1 Pure substances and mixtures, 3.2.2 Techniques for separating mixtures, 3.2.3 Paper chromatography and Rf values, and 3.2.4 Making water potable. Each one has a worked solution and a mark scheme showing where the marks go.

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