Heat of Formation

DH_{f is heat of formation of the given substance from its elements.  All values of} DH_{f are expressed} as kcal/mole at 25°C.  Negative values of DH_{f indicate exothermic reactions.  s = solid, l = liquid,} g = gas

Substance

Phase

DH_f

Substance

Phase

DH_f

aluminum oxide

s

-400.4

lead(II) nitrate

s

-108.0

ammonia

g

-11.02

lead(II) sulfate

s

-219.87

ammonium chloride

s

-75.15

lithium chloride

s

-97.58

ammonium sulfate

s

-282.23

lithium nitrate

s

-115.1

barium chloride

s

-205.1

lithium sulfate

s

-342.83

barium nitrate

s

-237.11

Magnesium chloride

aq

-190.46

barium sulfate

s

-352.1

magnesium chloride

s

-153.35

benzene

g

+19.82

magnesium oxide

s

-143.8

benzene

l

+11.71

magnesium sulfate

s

-307.1

calcium carbonate

s

-288.46

manganese (IV) oxide

s

-124.29

calcium chloride

s

-190.2

manganese (II) sulfate

s

-254.60

calcium hydroxide

s

-235.70

mercury(I) chloride

s

-63.39

calcium nitrate

s

-224.28

mercury(II) chloride

s

-53.6

calcium oxide

s

-151.80

mercury(II) fulminate

s

+64

calcium sulfate

s

-342.76

mercury(II) nitrate

s

-93.8

carbon (diamond)

s

0.45

mercury(II)oxide

s

-21.71

carbon (graphite)

s

0.00

methane

g

-17.89

carbon dioxide

g

-94.05

nitrogen dioxide

g

+7.93

carbon disulfide

g

+27.98

nitrogen monoxide

g

+21.57

carbon disulfide

l

+21.44

dinitrogen monoxide

g

+19.61

carbon monoxide

g

-26.42

dinitrogen pentoxide

g

+2.70

carbon tetrachloride

g

-22.90

dinitrogen pentoxide

s

-10.0

citric acid

aq

-329.34

dinitrogen tetroxide

g

+2.19

copper(II) nitrate

s

-72.4

oxygen (O₂)

g

0.00

copper(II) oxide

s

-37.6

ozone (O₃)

g

+34.1

copper(II) sulfate

s

-184.36

diphosphorus pentoxide

s

-713.2

copper(I) sulfide

s

-19.0

potassium bromide

s

-93.73

copper(II) sulfide

s

-12.7

potassium chloride

s

-104.18

ethane

g

-20.24

potassium hydroxide

s

-101.78

ethyne (acetylene)

g

+54.19

potassium iodide

s

-78.31

hydrogen (H₂)

g

0.00

potassium nitrate

s

-117.76

hydrogen bromide

g

-8.71

potassium  sulfate

s

-342.66

hydrogen chloride

g

-22.06

silicon dioxide (quartz)

s

217.72

hydrogen chloride

aq

-40.02

silver acetate

s

-95.3

hydrogen fluoride

g

-64.80

silver chloride

s

-30.37

hydrogen iodide

g

+6.33

silver nitrate

s

-29.73

hydrogen oxide (water)

g

-57.80

silver sulfide

s

-7.79

hydrogen oxide (water)

l

-68.32

sodium bromide

s

-86.38

hydrogen peroxide

g

-32.53

sodium chloride

s

-98.23

hydrogen peroxide

l

-44.88

sodium hydroxide

s

-101.99

hydrogen sulfide

g

-4.82

sodium nitrate

s

-111.54

iodine (I₂)

s

0.00

sodium sulfate

s

-330.90

iodine (I₂)

g

+14.92

sulfur dioxide

g

-70.94

iron(III) chloride

s

-95.48

sulfur trioxide

g

-94.58

iron(III) oxide

s

-197.0

tin(IV) chloride

l

-122.2

iron(II,  III) oxide

s

-267.3

zinc chloride

aq

-116.68

iron(II) sulfate

s

-221.9

zinc nitrate

s

-115.6

iron(II) sulfide

s

-23.9

zinc oxide

s

-83.24

lead (II) oxide

s

-52.12

zinc sulfate

s

-234.9

lead(IV) oxide

s

-65.6

zinc sulfide

s

-49.23

Heat of Formation Table Illustrating Reactions for Heats of Formations

Formation Equation

Molecule Formed

DH_f = kcal/mole

½ N_2(g) + 3/2H_2(g) àNH_3(g)

ammonia

-11.0

6C_(s)+3H_2(g) à C₆H_6(l)

benzene

+11.72

4C_(s)+ 5H_2(g)à C₄H_10(g)

butane

-29.5

Ca_(s)+C1_2(g)àCaC1_2(s)

calcium chloride

-190.0

Ca_(s)+C_(s)+ 3/2 O_2(g)àCaCO_3(s)

calcium carbonate

-288.5

Ca _(s) + ½O_2(g) à CaO_(s)

calcium oxide

-151.9

Ca_(s) + S_(s) + 2O_2(g)à CaSO_4(s)

calcium sulfate

-342.4

C_(s) + O_2(g) à CO_2(g)

carbon dioxide

-94.0

C_(s) + ½O_2(g) àCO_(g)

carbon monoxide

-26.4

C(graphite)à C (diamond)

diamond

+0.45

2C_(s) + 3 H_2(g) à C₂H_6(g)

ethane

-20.2

2C_(s) + 3H_2(g) + ½ O_2(g) à C₂H₅OH_(l)

ethanol

-66.4

2C_(s) + 2H_2(g) à C₂H_4(g)

ethene

+12.5

2C_(s) + H_2(g) à C₂H_2(g)

ethyne

+54.2

½ H_2(g) + ½ Cl_2(g) à HCl_(g)

hydrogen chloride

-22.1

½ H_2(g) + ½I_2(g) à HI_(g)

hydrogen iodide

+6.2

Hg_(l) + 2C_(s) + N_2(g) + 3/2 O_2(g) à HgC₂N₂O_3(s)

mercury fulminate

+64.10

C_(s) +H_2(g) + ½ O_2(g) à CH₂O_(l)

methanal

-27.7

C_(s) +2H_2(g) à CH_4(g)

methane

-17.9

H_2(g) + C_(s) + O_2(g) à HCOOH_(l)

methanoic acid

-97.8

1/2N_2(g) + O_2(g) à NO_2(g)

nitrogen dioxide

+8.1

1/2N_2(g) + ½ O_2(g) à NO_(g)

nitric oxide

 (nitrogen monoxide)

+21.6

8C_(s) + 9H_2(g) à C₈H_18(l)

octane

-49.8

3C_(s) + 4H_2(g) à C₃H_{8 (g)}

propane

-24.8

Na_(s) + ½ Cl_2(g) à NaCl_(s)

sodium chloride

-98.2

S_(s) + O_2(g) à SO_2(g)

sulfur dioxide

-71.0

S_(s) +3/2 O_2(g) à SO_3(g)

sulfur trioxide

-94.5

H_2(g) + S_(s) + 2O_2(g) à H₂SO_4(l)

sulfuric acid

-194.0

H_2(g) +1/2 O_2(g) à H₂O_(l)

water

-68.3

H_2(g) +1/2 O_2(g) à H₂O_(g)

water vapor

-57.8