The value of δ H_sol of anhydrous copper (II) sulphate is -66.11 kJ. Dissolution of 1 mole of blue v — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

Dissolution of anhydrous $CuSO_4$: $CuSO_4$(s) + aq -> $CuSO_4$(aq), δ H = -66.11 kJ. Dissolution of blue vitriol: $CuSO_4$.5$H_2O$(s) + aq -> $CuSO_4$(aq), δ H = +11.5 kJ. We want dehydration reaction: $CuSO_4$.5$H_2O$(s) -> $CuSO_4$(s) + 5$H_2O$(l). By Hess's law, this reaction is the difference: δ H = 11.5 - (-66.11) = +77.61 kJ.