Ethanol can be made by fermentation of sugar or by reacting ethene with steam.
Reacting ethene with steam has an atom economy of 100 %.
Which is the best reason why a company might still choose fermentation?
Fermentation uses a renewable raw material that can be regrown each year
Fermentation has a higher atom economy because carbon dioxide is useful
Fermentation gives a higher yield because the reaction is not reversible
Fermentation produces ethanol faster because it uses enzymes as catalysts
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.