Use Hess's law to determine ArH for the reaction: C3H4 (g) + 2H2(g) C3H3 (2) Given the: H2(g) + 0(g) H, 0(1) 4. H = -285.8 kJ mol-1 CH_(8) +402(g) 3C02(g) + 2 H2O(1) A,H = -1937 kJ mol-1 C,H, (g) +502(g) + CO2(g) + 4H2O(1) A.H = -2219.1 kJ mol-1