A student attempts to synthesise a pure sample of the insoluble salt barium sulfate (BaSO4\text{BaSO}_4BaSO4) by mixing solutions of barium chloride and sodium sulfate.
The student calculates that they should theoretically obtain 4.50 g of barium sulfate precipitate. After filtering, washing with distilled water, and drying the precipitate, the actual mass of barium sulfate recovered is 3.92 g, giving a percentage yield of 87.1%.
Give two reasons why the actual yield in a practical preparation of an insoluble salt like this is 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.