Edexcel IGCSE Chemistry 1.30 percentage yield
Practise percentage-yield questions by finding theoretical mass, applying actual yield and explaining experimental results above 100%.
- Syllabus
- First assessment 2019
- Course
- Chemistry 4CH1
Exam points
- Calculate percentage yield from actual mass divided by theoretical mass, then multiply by 100.
- Use balanced equations and Mr values to find theoretical mass before applying yield.
- Explain yields above 100% using wet crystals, weighing error or contamination of product.
1.30 Percentage yield question 1
[Maximum number: 2]
A sample of iron(III) oxide reacts with excess carbon monoxide.
This is the equation for the reaction.
Fe2O3+3CO→2Fe+3CO2
The actual yield of iron from this sample is 21 g .
Calculate the percentage yield of iron.
- 21 / 28 x 100
- 75%
Allow:
- ECF for any correct calculation involving 21 as the numerator
Marking guidance:
- Correct answer without working scores 2.
- 0.75 scores 1.
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