A student makes insoluble barium sulfate by mixing solutions of barium chloride and sodium sulfate.
BaCl2(aq)+Na2SO4(aq)→BaSO4(s)+2NaCl(aq)\mathrm{BaCl_{2}(aq)} + \mathrm{Na_{2}SO_{4}(aq)} \rightarrow \mathrm{BaSO_{4}(s)} + \mathrm{2NaCl(aq)}BaCl2(aq)+Na2SO4(aq)→BaSO4(s)+2NaCl(aq)
She dissolves 5.20 g of barium chloride and 4.26 g of sodium sulfate in separate beakers of water, then mixes the solutions. She filters off the precipitate, washes it and dries it.
Relative formula masses: BaCl2=208,Na2SO4=142,BaSO4=233\mathrm{BaCl_{2}} = 208, \mathrm{Na_{2}SO_{4}} = 142, \mathrm{BaSO_{4}} = 233BaCl2=208,Na2SO4=142,BaSO4=233, NaCl = 58.5
Show by calculation which reactant is the limiting reactant.
Calculate the theoretical yield of barium sulfate.
The student obtains 5.24 g of dry barium sulfate. Calculate the percentage yield. Give your answer to three significant figures.
Explain two reasons, linked to this method, why the actual yield is less than the theoretical yield.
Another student calculates a percentage yield of 106 %. Suggest one reason for this.
Calculate the atom economy for making barium sulfate by this reaction.
51 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.