Barium sulfate is made using the reaction:
BaCl2+Na2SO4→BaSO4+2NaCl\mathrm{BaCl_2 + Na_2SO_4 \rightarrow BaSO_4 + 2NaCl}BaCl2+Na2SO4→BaSO4+2NaCl
A manufacturer reacts 20.8 g of barium chloride with excess sodium sulfate.
Relative formula masses (MrM_rMr):
BaCl2=208\mathrm{BaCl_2} = 208BaCl2=208
BaSO4=233\mathrm{BaSO_4} = 233BaSO4=233
The solid barium sulfate is separated from the reaction mixture and weighed before and after drying.
| Measurement | Mass of solid in g |
|---|---|
| Before drying | 24.1 |
| After drying | 21.7 |
Calculate the percentage yield using the mass before drying and the percentage yield using the mass after drying.
Explain which calculated value should be reported as the percentage yield.
104 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.