Question

The heat of solution of anhydrous CuSO$_4$ and CuSO$_4\cdot$5H$_2$O are $-70$ kJ mol$^{-1}$ and $+12$ kJ mol$^{-1}$ respectively. The heat of hydration of CuSO$_4$ to CuSO$_4\cdot$5H$_2$O is $-x$ kJ. The value of $x$ is _____.

Answer 1

Correct Answer: 82

The heat of hydration of CuSO₄ to CuSO₄ · 5H₂O is given by the difference between the heat of solution of anhydrous CuSO₄ and CuSO₄ · 5H₂O.

Heat of hydration = Heat of solution of anhydrous CuSO₄ − Heat of solution of CuSO₄ · 5H₂O.

Substitute the values:

\( x = \left| -70 \, \text{kJ mol}^{-1} - \left( +12 \, \text{kJ mol}^{-1} \right) \right| \).

\( x = \left| -70 - 12 \right| = \left| -82 \right| = 82 \).

Final Answer: 82 kJ.