need help with practice problem 1

Example Cao(s) + H2O(1) + Ca(OH)2(s) AH= ? A,H CaO(s) = -634.9 kJ/mol AfH H2O(1) = -285.8 kJ/mol AfH Ca(OH)2(s) = -985.2 kJ/mol Formation enthalpies from data booklet AH = [ 1(-985.2 kJ/mol)] - [1(-634.9 kJ/mol) + 1(-285.8 kJ/mol)] = -64.5 kJ * The lower the value of a compound's standard molar enthalpy of formation, more stable the compound is (less energy = greater stability) PRACTICE PROBLEMS 1. Predict the standard enthalpy change of the following reaction: C3H8(g) +502(g) 3C02(g) + 4H2O(1)