Ammonia is made from nitrogen and hydrogen.
The percentage yield is less than 100 % even when no ammonia is lost during separation.
Which statement explains why?
The atoms in the reactants are not all conserved when ammonia forms
The reaction also makes a waste product, which lowers the yield
The mass of the products is always less than the mass of the reactants
The reaction is reversible, so some ammonia changes back into reactants
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.