Hess's law exercise answer

We need to carry out two plastic cup experiments and then use Hess's Law to show DH = DH₁ - DH₂. DH₁ is the enthalpy change for the reaction in which anhydrous copper(II) sulfate (CuSO₄(s)) is dissolved in water. DH₂ is the enthalpy change for the reaction in which hydrated copper(II) sulfate (CuSO₄.5H₂O(s)) is dissolved in water.

We need to choose an appropriate volume of water and mass of copper(II) sulfate. Ideally, we shall choose a large enough mass of copper(II) sulfate in order to give a reasonable temperature change. However, we don't want to use too large a mass in case it doesn't all dissolve, or dissolves very slowly. If we are being precise, we should also allow for the water contained in the hydrated copper(II) sulfate, and so use a reduced amount of water for the solution in this case.