for the chemical reaction h2 + co2 → h2o + co, the energy contained in the reactants is 394 kj, and the energy contained in the products is 352 kj, assuming 1 mol of each substance is present. which of the following statements is true? a. 42 kj is released, and the reaction is exothermic. b. 42 kj is absorbed, and the reaction is exothermic. c. 42 kj is absorbed, and the reaction is endothermic. d. 42 kj is released, and the reaction is endothermic