Question 1: Define what a salt is in terms of chemical composition.

Answer: A salt is an ionic compound formed from the neutralisation of an acid by a base, consisting of a metal or ammonium ion and a non-metal or polyatomic ion.

Question 2: Explain the general process of making a salt by titration and subsequent crystallisation.

Answer: The process involves reacting an acid with an excess of a base or metal, then filtering to remove impurities, and evaporating or cooling the solution to crystallise the salt.

Question 1: Calculate the mass of sodium chloride (NaCl) produced when 0.5 mol of hydrochloric acid reacts completely with excess sodium hydroxide. (Molar mass of NaCl = 58.44 g/mol, HCl = 36.46 g/mol)

Answer: 58.22 grams

Question 2: If you start with 25.0 cm³ of 0.1 mol/dm³ sulphuric acid, how much copper sulphate (CuSO₄) can be theoretically formed? (Molar mass of CuSO₄ = 159.61 g/mol)

Answer: 0.399 g

Question 1: List three safety precautions that should be observed when preparing salts in the laboratory.

Answer: Wear safety goggles, handle acids and bases with care, and work in a well-ventilated area.

Question 2: Identify the variables that need to be controlled during the crystallisation process.

Answer: Temperature, concentration of the solution, and rate of cooling.

Question 1: A student reacts 50 cm³ of 0.2 mol/dm³ hydrochloric acid with excess sodium hydroxide and obtains 4.6 grams of sodium chloride. Does this match the theoretical yield? (Molar mass of NaCl = 58.44 g/mol)

Answer: Theoretical yield is approximately 1.17 grams; the actual yield is much higher, indicating an error or impurity.

Question 1: Describe the steps involved in making a soluble salt, including the purpose of each step. (6 marks)

Answer: First, react an acid with an excess of a base or metal to ensure complete neutralisation. Filter the solution to remove impurities. Then, evaporate or cool the solution to crystallise the salt. Finally, dry the crystals for use.

Question 1: Explain how salts are produced on an industrial scale for use in fertilisers.

Answer: Salts are produced by large-scale neutralisation of acids with bases, often using industrial reactors, to produce compounds like ammonium nitrate and potassium sulphate for fertilisers.