Table of Some Standard Enthalpies of Formation at 25°C

Submitted by ChemPRIME Staff on Thu, 12/09/2010 - 14:02

Compound ΔHf/kJ

mol–1

ΔHf/kcal

mol–1

Compound ΔHf/kJ

mol–1

ΔHf/kcal

mol–1

AgCl(s)
–127.068
–30.35
H2O(g)
–241.818
–57.79
AgN3(s)
+620.6
+148.3
H2O(l)
–285.8
–68.3
Ag2O(s)
–31.0
–7.41
H2O2(l)
–187.78
–44.86
Al2O3(s)
–1675.7
–400.40
H2S(g)
–20.63
–4.93
Br2(l)
0.0
0.00
HgO(s)
–90.83
–21.70
Br2(g)
+30.907
+7.385
I2(s)
0.0
0.0
C(s), graphite
0.0
0.00
I2(g)
+62.438
+14.92
C(s), diamond
+1.895
+0.453
KCl(s)
–436.747
–104.36
CH4(g)
–74.81
–17.88
KBr(s)
–393.798
–94.097
CO(g)
–110.525
–26.41
MgO(s)
–601.7
–143.77
CO2(g)
–393.509
–94.05
NH3(g)
–46.11
–11.02
C2H2(g)
+226.73
+54.18
NO(g)
+90.25
+21.57
C2H4(g)
+52.26
+12.49
NO2(g)
+33.18
+7.93
C2H6(g)
–84.68
–20.23
N2O4(g)
+9.16
+2.19
C6H6(l)
+49.03
+11.72
NF3(g)
–124.7
–29.80
CaO(s)
–635.09
–151.75
NaBr(s)
–361.062
–86.28
CaCO3(s)
–1206.92
–288.39
NaCl(s)
–411.153
–98.24
CuO(s)
–157.3
–37.59
O3(g)
+142.7
+34.11
Fe2O3(s)
–824.2
–196.9
SO2(g)
–296.83
–70.93
HBr(g)
–36.4
–8.70
SO3(g)
–395.72
–94.56
HCl(g)
–92.307
–22.06
ZnO(s)
–348.28
–83.22
HI(g)
+26.48
+6.33

Above is a table of standard enthalpies of formation at 25°C. This is the enthalpyA thermodynamic state function, symbol H, that equals internal energy plus pressure x volume; the change in enthalpy corresponds to the energy transferred as a result of a temperature difference (heat transfer) when a reaction occurs at constant pressure. change which occurs when a compound is formed from its constituent elements. For instance, the enthalpy of formationThe enthalpy change that occurs during the formation of a compound from its component elements in their most stable forms. See also standard enthalpy of formation. value of ΔHm = –285.8 kJ mol–1 is the enthalpy change for the reaction: H2(g) + ½O2(g) → H2O(l). It is important to note that the enthalpy of formation for an element in its most stable state is 0. Using these enthalpies of formation and Hess' Law the enthalpy change of any reaction involving the compounds with a known enthalpy of formation can be determined.

This table is found on CoreChem:Standard Enthalpies of Formation