Consider the following reaction: 2 Mg(s) + O2 → 2 MgO(s) a. Is the reaction exothermic or endothermic? b. calculate the amount of heat transferred when 3 g of Mg(s) reacts at constant pressure. c. How many grams of MgO are produced during an enthalpy change of 100.0 kJ? d. How many kilo joules of heat are absorbed when 8 g of MgO(s) are decomposed into Mg(s) and O2(g) at constant pressure? AH = -1204 kJ.