A student prepares a sample of zinc sulfate crystals by reacting zinc carbonate with dilute sulfuric acid. The student's calculated theoretical yield was 12.5 g, but they only obtained an actual yield of 9.1 g, giving a percentage yield of 72.8%.
Give two reasons why the actual yield in a practical chemical preparation like this is usually less than the theoretical yield.
157 exam-style questions on Edexcel GCSE Chemistry 6.2 Quantitative analysis, covering 6.2.1 Concentration in mol dm⁻³ and titration calculations, 6.2.2 Percentage yield and why actual yield falls short, 6.2.3 Atom economy of a reaction, 6.2.4 Choosing a reaction pathway, and 6.2.5 Molar volume of gases and Avogadro's law. Each one has a worked solution and a mark scheme showing where the marks go.