A.442.3kJ•mol-1 B.260.7kJ•mol-1 C.–442.3kJ•mol-1 D.-260.7kJ•mol-1
A.C(s)+O2(g)→CO2(g) B.2SO2(g)+O2(g)→2SO3(g) C.3H2(g)+N2(g)→2NH3(g) D.CuSO4(s)+5H2O(l)→CuSO4•5H2O(s)