To calculate the standard enthalpy change for the reaction, we need to use the following equation:H = q / nwhere H is the standard enthalpy change, q is the heat released or absorbed during the reaction, and n is the number of moles of the limiting reactant.First, we need to write the balanced chemical equation for the reaction:CaO s + H2O l Ca OH 2 s Now, we need to find the number of moles of calcium oxide CaO in 3.2 grams:Molar mass of CaO = 40.08 g/mol Ca + 16.00 g/mol O = 56.08 g/moln CaO = mass / molar mass = 3.2 g / 56.08 g/mol = 0.0571 molNext, we need to find the standard enthalpy change for the reaction. The standard enthalpy of formation for calcium oxide CaO is -635.1 kJ/mol, and for calcium hydroxide Ca OH 2 is -985.2 kJ/mol. Using Hess's Law, we can calculate the standard enthalpy change for the reaction:H reaction = Hf products - Hf reactants H reaction = [1 mol -985.2 kJ/mol ] - [1 mol -635.1 kJ/mol ]H reaction = -985.2 kJ/mol + 635.1 kJ/mol = -350.1 kJ/molNow, we can calculate the heat released q during the reaction:q = n H reaction = 0.0571 mol -350.1 kJ/mol = -20.0 kJSince the value is negative, it means the reaction is exothermic and releases heat.Finally, we can calculate the standard enthalpy change for the reaction:H = q / n = -20.0 kJ / 0.0571 mol = -350.1 kJ/molThe standard enthalpy change for the reaction of calcium oxide and water to form calcium hydroxide is -350.1 kJ/mol.