1.1. A sample of hydrated copper sulphate, CuSO₄.xH₂O, has a relative formula mass of 285.5. 

Calculate a value for ‘x’. Give your answer to 2 decimal places.

1.2. A student completed an experiment to determine the value of ‘x’ in a hydrated salt. They heated a solid sample of the salt, CuSO₄.xH₂O, in a crucible for 60 seconds and recorded the following set of results.

Table 1

Use the data obtained by the student in Table 1 to calculate a value for ‘x’. Give your answer to 2 decimal places.

1.3. The actual value for x in CuSO₄.xH₂O is 5.

i) Suggest a reason for the discrepancy between your calculated value and the actual value.

ii) Suggest how you could improve the experiment the student did, using the same equipment, to achieve a value closer to the correct value for x. (If you did not achieve a value for x, assume that x = 3.50. This is not the correct answer.)

1.4. Copper (II) sulfate undergoes a displacement reaction with magnesium, because magnesium is a more reactive metal than copper.

i) Write a balanced equation with state symbols for this reaction.

ii) Calculate the atom economy of the magnesium product which is formed.