n a laboratory experiment, a chemist wants to empirically determine the enthalpy change for the following reaction: Mg(s) + 2 HCI(aq) - MgCl2(aq) + H2(8) The chemist uses a simple calorimeter and reacts 0.466 g of magnesium ribbon with 100 mL of 1.00 mol/L HClag). The initial temperature of the HCl(ag) is 20.1.C. After the reaction, the highest recorded temperature is 40.3.C. The enthalpy change of Mgig is abc kJ/mol