CAIE IGCSE Chemistry 3.3.8 Percentage yield, percentage

Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise percentage yield, composition and purity calculations from equations, masses and formulae in common inorganic reactions.

How this is tested

calculate percentage yield from actual mass and theoretical mass from the equation
find percentage composition by mass using Mr and the mass of the named element
use percentage composition data to compare ores or compounds as better extraction sources

[Maximum number: 1]

When heated, copper(II) oxide, CuO , reacts with ammonia, $\mathrm{NH}_{3}$ .

3 \mathrm{CuO}+2 \mathrm{NH}_{3} \rightarrow 3 \mathrm{Cu}+\mathrm{N}_{2}+3 \mathrm{H}_{2} \mathrm{O}

8.5 g of ammonia reacts with an excess of copper(II) oxide to produce 26.4 g of copper.

What is the percentage yield of copper in this reaction?

27.5%

32.2\%

55.0\%

82.5\%