Standard Heat/ Standard Empalthy...?

Question

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

Answer 1

2 H3PO4 + 3 Ca(OH)2 -> Ca3(PO4)2 + 6 H2O