Quantitative analysis
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A sample of solid sodium carbonate contained soluble, unreactive impurities.

A student tried to find the mass of pure sodium carbonate in the sample, using the following method.

  • step 1 Measure the mass of the sample of impure sodium carbonate.
  • step 2 Dissolve the sample in 100 cm3 of distilled water in a beaker.
  • step 3 Use a measuring cylinder to transfer 25.0 cm3 of this sodium carbonate solution into a conical flask.
  • step 4 Add 3 drops of methyl orange indicator to the flask.
  • step 5 Place the conical flask on a white tile.
  • step 6 Add dilute hydrochloric acid of known concentration from a burette, swirling continuously.
  • step 7 Stop when the indicator changes colour.
  • step 8 Record the volume of hydrochloric acid added.
  • step 9 Use this single titration measurement to calculate the mass of pure sodium carbonate in the sample.

Suggest three improvements to this method to obtain a more accurate mass of pure sodium carbonate.

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Quantitative analysis Questions

Practise Edexcel GCSE Chemistry Quantitative analysis with exam-style questions for Foundation and Higher tier. 100 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.

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Quantitative analysis Questions

  1. GCSE
  2. /Chemistry
  3. /Quantitative analysis