A pilot plant is comparing two pathways for making compound R. For each batch, the maximum theoretical mass of compound R is the same for both pathways.
| Measurement | Pathway A | Pathway B |
|---|---|---|
| Atom economy | 100 % | 65 % |
| Percentage yield | 55 % | 90 % |
| Time for one batch | 8 h | 2 h |
The plant can use either pathway, and the product from each pathway is the same.
Which statement best supports choosing pathway B?
Pathway B collects more compound R from each batch and can complete more batches in the same time
Pathway B has a higher maximum theoretical mass of compound R because its percentage yield is higher
Pathway B has a higher percentage yield, so none of its reactant mass is wasted as by-products
Pathway B wastes less reactant mass as by-products and turns more of each reactant into compound R
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.