An analyst is preparing a pure sample of magnesium sulfate heptahydrate crystals (MgSO4⋅7H2O\text{MgSO}_4\cdot7\text{H}_2\text{O}MgSO4⋅7H2O) by reacting excess magnesium oxide powder with a measured volume of dilute sulfuric acid.
After filtering off the unreacted solid, crystallising the filtrate, and drying the collected crystals, the analyst finds that the actual mass of the crystals obtained is greater than the calculated maximum theoretical yield.
Suggest one chemical reason, other than weighing errors, why the recorded actual yield of the crystals was greater than the theoretical yield.
276 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.