O-LevelChemistryStoichiometry5070/11 · May/June 2014 · Q101 Mark

A piece of chalk has a mass of 23.0g. Chalk is impure calcium carbonate. When analysed, the chalk is found to contain 0.226 moles of pure calcium carbonate. [Mᵣ: CaCO₃, 100] What is the percentage purity of the piece of chalk?

A0.983%

B1.02%

C77.0%

D98.3%

✓ Correct answer

D: 98.3%

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Topic: Stoichiometry, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2014 Paper 1 Variant 1, question 10.

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