Thermochemistry Table for Common Compounds

The molar heat of formation of a compound (ΔH_f) is equal to its enthalpy change (ΔH) when one mole of compound is formed at 25°C and 1 atm from elements in their stable form. This is a table of the heats of formation for a variety of common compounds. As you can see, most heats of formation are negative quantities, which implies that the formation of a compound from its elements usually is an exothermic process.

Compound	ΔHf (kJ/mol)	Compound	ΔHf (kJ/mol)
AgBr(s)	-99.5	C2H2(g)	+226.7
AgCl(s)	-127.0	C2H4(g)	+52.3
AgI(s)	-62.4	C2H6(g)	-84.7
Ag2O(s)	-30.6	C3H8(g)	-103.8
Ag2S(s)	-31.8	n-C4H10(g)	-124.7
Al2O3(s)	-1669.8	n-C5H12(l)	-173.1
BaCl2(s)	-860.1	C2H5OH(l)	-277.6
BaCO3(s)	-1218.8	CoO(s)	-239.3
BaO(s)	-558.1	Cr2O3(s)	-1128.4
BaSO4(s)	-1465.2	CuO(s)	-155.2
CaCl2(s)	-795.0	Cu2O(s)	-166.7
CaCO3	-1207.0	CuS(s)	-48.5
CaO(s)	-635.5	CuSO4(s)	-769.9
Ca(OH)2(s)	-986.6	Fe2O3(s)	-822.2
CaSO4(s)	-1432.7	Fe3O4(s)	-1120.9
CCl4(l)	-139.5	HBr(g)	-36.2
CH4(g)	-74.8	HCl(g)	-92.3
CHCl3(l)	-131.8	HF(g)	-268.6
CH3OH(l)	-238.6	HI(g)	+25.9
CO(g)	-110.5	HNO3(l)	-173.2
CO2(g)	-393.5	H2O(g)	-241.8
H2O(l)	-285.8	NH4Cl(s)	-315.4
H2O2(l)	-187.6	NH4NO3(s)	-365.1
H2S(g)	-20.1	NO(g)	+90.4
H2SO4(l)	-811.3	NO2(g)	+33.9
HgO(s)	-90.7	NiO(s)	-244.3
HgS(s)	-58.2	PbBr2(s)	-277.0
KBr(s)	-392.2	PbCl2(s)	-359.2
KCl(s)	-435.9	PbO(s)	-217.9
KClO3(s)	-391.4	PbO2(s)	-276.6
KF(s)	-562.6	Pb3O4(s)	-734.7
MgCl2(s)	-641.8	PCl3(g)	-306.4
MgCO3(s)	-1113	PCl5(g)	-398.9
MgO(s)	-601.8	SiO2(s)	-859.4
Mg(OH)2(s)	-924.7	SnCl2(s)	-349.8
MgSO4(s)	-1278.2	SnCl4(l)	-545.2
MnO(s)	-384.9	SnO(s)	-286.2
MnO2(s)	-519.7	SnO2(s)	-580.7
NaCl(s)	-411.0	SO2(g)	-296.1
NaF(s)	-569.0	So3(g)	-395.2
NaOH(s)	-426.7	ZnO(s)	-348.0
NH3(g)	-46.2	ZnS(s)	-202.9

Reference: Masterton, Slowinski, Stanitski, Chemical Principles, CBS College Publishing, 1983.