The diagram below shows the energy changes that occur when sodium chloride dissolves in water. Study it and answer the questions that follow.
![sukchempp1q05](https://www.easyelimu.com/images/mockpastpapers/sukellemo_2020/sukchempp1q05.PNG)
- What do ∆H1, ∆H2 and ∆H3 represent?
- Given that the lattice energy of NaCl (s) is -776 kJmol-1 and hydration energies of Na+(g) and Cl-(g) are -407 kJmol-1 and -364 kJmol-1 respectively. Calculate the heat of solution (∆Hsol) of 1 mole NaCl (s).