Question

What is the ΔHsol for LiBr → Li+ + Br-? The lattice energy is -734 kJ/mol, the enthalpy of hydration for Li+ is -499 kJ/mol, and the enthalpy of hydration for Br- is -284 kJ/mol. Use ΔHsol = -ΔHlat + ΔHydr.

a) 519 kJ/mol
b) -49 kJ/mol
c) 49 kJ/mol
d) 1,517 kJ/mol

Answer 1

The ΔHsol for LiBr → Li+ + Br- is -49 kJ/mol.

Step-by-step explanation:

ΔHsol can be calculated using the equation ΔHsol = -ΔHlat + ΔHydr. In this case, the enthalpy of solution is the sum of the lattice energy and the enthalpies of hydration for the dissociated ions. The lattice energy for LiBr is given as -734 kJ/mol, and the enthalpy of hydration for Li+ is -499 kJ/mol, and for Br- is -284 kJ/mol. To calculate ΔHsol, we substitute the given values into the equation: ΔHsol = -(-734) + (-499) + (-284) = 734 - 499 - 284 = -49 kJ/mol.