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AQA · GCSE · Chemistry · Higher

Recognising excess copper carbonate

Q01.2 1 mark

A student produced a salt by reacting copper carbonate with sulfuric acid.

  1. Measure 50 cm³ of sulfuric acid into a beaker.
  2. Add copper carbonate powder.
  3. Stir the mixture.
  4. Repeat steps 2 and 3 until copper carbonate is in excess.
  5. Filter the mixture.
  6. Warm the filtrate gently until crystals start to appear.
  7. Leave the solution to cool and crystallise.

Give one observation the student could make during Step 4 which shows that the copper carbonate is in excess.

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Marking points

  1. 1 States one valid visible sign that added copper carbonate is no longer reacting.

Full-mark answer

Some solid copper carbonate remains in the mixture after stirring.

Why this answer loses marks

The mixture changes colour.

Colour is not credited here; use a visible sign that added solid no longer reacts.

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