Write down a balanced equation for the reaction of the calcium hydroxide, Ca(OH)2, with phosphoric acid, H3PO4, producing the water, H2O and the calcium phosphate, Ca3(PO4)2. Determine the heat of reaction from the standard heats of formation listed below. Then, describe the standard enthalpy change when the 42.4 grams of phosphoric acid is consumed in this reaction. Standard heat of formation (Ca(OH)2) -986kJ/mol standard heat of formation(H3PO4) -1279 kJ/mol standard heat of formation(Ca3(PO4)2) -4132 kJ/mol standard heat of formation (H2O) -285 kJ/mol.