Balanced equations, yield and atom economyAQA A-Level Chemistry: Mind map

Exam questions on Balanced equations, yield and atom economy

1. Ethanol can be manufactured by two methods. In the hydration of ethene, C₂H₄ + H₂O → C₂H₅OH. In the fermentation of glucose, C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂. Relative formula masses: C₂H₄ = 28.0, H₂O = 18.0, C₂H₅OH = 46.0, C₆H₁₂O₆ = 180.0.
   A company chooses the hydration method. Explain two advantages to society and the environment of using a process with a high atom economy.2 marks
2. A student titrates 25.0 cm³ portions of sodium hydroxide solution with 0.100 mol dm⁻³ hydrochloric acid, using an indicator. The mean titre is 22.40 cm³.
   Calculate the concentration, in mol dm⁻³, of the sodium hydroxide solution.2 marks
3. A student prepares a standard solution of sodium carbonate to use in a titration with hydrochloric acid. She needs 250 cm³ of a solution of concentration 0.0500 mol dm⁻³, made using anhydrous sodium carbonate, Na₂CO₃ (Mr = 106.0).
   Calculate the mass of anhydrous sodium carbonate she should weigh out.3 marks