Calcium oxide (lime) is made by heating calcium carbonate (limestone).
CaCO3→CaO+CO2 \mathrm{CaCO_{3}} \rightarrow \mathrm{CaO} + \mathrm{CO_{2}} CaCO3→CaO+CO2Which statement describes the atom economy of a reaction?
Statement 1: The mass of product actually made compared with the maximum mass that could be made.
Statement 2: The percentage of the mass of the reactants that ends up in the desired product.
Statement 3: The number of atoms in one molecule of the desired product.
Statement 4: How quickly the reactants are changed into products.
Write the number of the correct statement.
Calculate the atom economy for making calcium oxide in this reaction.
Use the equation: atom economy = (Mr of desired product ÷ total Mr of all products) × 100
Mr of CaO = 56.1 and Mr of CO2\mathrm{CO_{2}}CO2 = 44.0
Atom economy = ...... %
A company heats 1000 tonnes of calcium carbonate. The maximum mass of calcium oxide that could be made is 560 tonnes. The company actually makes 504 tonnes of calcium oxide.
Calculate the percentage yield.
Use the equation: percentage yield = (actual yield ÷ theoretical yield) × 100
Percentage yield = ...... %
Suggest two reasons why the actual yield is less than the theoretical yield.
The carbon dioxide made in this reaction is a waste product.
Give one disadvantage of a reaction that has a low atom economy.
57 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.