Calculate the free energy change when 1 mole of NaCl is dissolved in water at 298 K. (Given : Lattice energy of NaCl = -777.8 kJ mol^(-1)), Hydration energy -774.1 kJ mol^(-1) and Delta S = 0.043 kJ mol^(-1) mol^(-1) at 298 K).

Calculate the free energy change when 1 mole of NaCl is dissolved in w

1.	Calculate the free energy change when 1 mole of NaCl is dissolved in water at 298 K. (Given : Lattice energy of NaCl = -777.8 kJ mol^(-1)), Hydration energy -774.1 kJ mol^(-1) and Delta S = 0.043 kJ mol^(-1) mol^(-1) at 298 K).
Answer» Solution :`Delta H` - HYDRATION ENERGY - Lattice energy `Delta H = -774.1 KJ mol^(-1) (-777.8 kJ mol^(-1))= 3.7 kJ mol^(-1)` `Delta G = Delta H - T Delta S = +3.7 kJ - 298 xx 0.043 kJ = +3.7 kJ - 12.81 kJ` `Delta G = -9.11 kJ mol^(-1)`.