Question

What is the Hsol for KBr k+ + br- ? The lattice energy is –679 kJ, the enthalpy of hydration for is –336 kJ/mol, and the enthalpy of hydration for is –284 kJ/mol. Use Hsol = –Hlat + Hhydr. –627 kJ/mol –59 kJ/mol 59 kJ/mol 1,299 kJ/mol

Answer 1

The enthalpy change of the solution represents the change in enthalpy when one mole of a certain ionic substance would dissolve in water. It can be calculated from the sum of the lattice energy and the enthalpy of hydration. We calculate as follows:

Hsol = 679 kJ + –336 kJ/mol +  –284 kJ/mol = 59 kJ/mol