The reaction between calcium metal and chlorine gas is described by the following thermochemical equation: Ca(s) + Cl2(g) = CaCl2(s) ΔH = -796 kJ mol-1 What will be the enthalpy change (to 2 significant figures) for the reaction when 4.0 g of calcium metal reacts with chlorine gas at constant pressure? The relative atomic mass of calcium is 40. ΔH = to 2 significant figures.