Grossmont College Magnesium Bromide and Heat of Solution Worksheet

1. Magnesium bromide, MgBr2, has a lattice energy, (delta H)lattice, of -2406.0 kJ/mol and a heat of hydration, (delta H )hydration, of -2591.6 kJ/mol.

Calculate the heat of solution, (delta H)solution, for magnesium bromide.

2. Order the following compounds by rewriting them from left to right in order of decreasing heat of hydration (most exothermic to least exothermic).

CaBr2 ,MgBr2 ,NaBr, NaI, SrBr2, SrI2

3. Write a dissolution equation for Al(NO3)3 and use it as a basis for a Hess’s law type calculation to determine the heat of hydration of a nitrate ion,( delta H )hydration (NO3-), given:

delta H solution Al(NO3)3 = 174.0 kJ/mol

delta H lattice Al(NO3)3 = -5796.0 kJ/mol

dellta H hydration (Al3+) = -4680.0 kJ/mol