A student added an excess of copper oxide to dilute sulfuric acid and made copper sulfate crystals. The percentage yield of copper sulfate crystals was 62 %. Which statement explains why the percentage yield was less than 100 %?
Some of the copper oxide was added in excess to the sulfuric acid
Some of the sulfuric acid was measured using a measuring cylinder
Some of the copper sulfate crystals were weighed before they were dry
Some of the copper sulfate solution was left behind in the beaker
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.