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3.3 Yield and atom economy of chemical reactions

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Question 2
H

Ammonia is made from nitrogen and hydrogen.

N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3N2​+3H2​→2NH3​

A factory reacts 1.40 tonnes of nitrogen with an excess of hydrogen.

Relative atomic masses: H=1\text{H} = 1H=1, N=14\text{N} = 14N=14.

a.

Calculate the maximum theoretical mass of ammonia, in tonnes, that could be made from 1.40 tonnes of nitrogen.

[3]
b.

The factory made 1.36 tonnes of ammonia. Calculate the percentage yield of ammonia.

[2]
c.

Give one reason why the percentage yield of ammonia is less than 100 %, even though the hydrogen is in excess.

[1]
Markscheme

3.3 Yield and atom economy of chemical reactions Questions

  1. GCSE
  2. /Chemistry
  3. /3.3 Yield and atom economy of chemical reactions

39 exam-style questions on AQA GCSE Chemistry 3.3 Yield and atom economy of chemical reactions, covering 3.3.1a Percentage yield, 3.3.1b Theoretical mass of a product, 3.3.2a Atom economy, and 3.3.2b Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.

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