Consider the following reaction at 2488c and 1.00 atm: ch3cl(g) 1 h2(g) 88n ch4(g) 1 hcl(g) for this reaction, the enthalpy change at 2488c is 283.3 kj/mol. at constant pressure the molar heat capacities (cp) for the compounds are as follows: ch3cl (48.5 j k21 mol21), h2 (28.9 j k21 mol21), ch4 (41.3 j k21 mol21), and hcl (29.1 j k21 mol21).