## 2 C12H26 (ℓ 1-dodecane) + 37 O2 (g) → 24 CO2 (g) + 26 H2O (g)

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Combustion

## Stoichiometry

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 C12H26         Mass: g O2             Mass: g or Gas Volume: L CO2            Mass: g or Gas Volume: L H2O            Mass: g or Gas Volume: L Heat Released: kJ

## Enthalpy of Reaction

[24ΔHf(CO2 (g)) + 26ΔHf(H2O (g))] - [2ΔHf(C12H26 (ℓ 1-dodecane)) + 37ΔHf(O2 (g))]
[24(-393.51) + 26(-241.82)] - [2(-352.13) + 37(0)] = -15027.3 kJ
-15,027.30 kJ     (exothermic)

## Entropy Change

[24ΔSf(CO2 (g)) + 26ΔSf(H2O (g))] - [2ΔSf(C12H26 (ℓ 1-dodecane)) + 37ΔSf(O2 (g))]
[24(213.68) + 26(188.72)] - [2(490.62) + 37(205.03)] = 1467.69 J/K
1,467.69 J/K     (increase in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[24ΔGf(CO2 (g)) + 26ΔGf(H2O (g))] - [2ΔGf(C12H26 (ℓ 1-dodecane)) + 37ΔGf(O2 (g))]
[24(-394.38) + 26(-228.59)] - [2(28.07) + 37(0)] = -15464.6 kJ
-15,464.60 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-15464.89 kJ     (spontaneous)

## Equilibrium Constant, K (at 298.15 K)

approaches infinity
This process is favorable at 25°C.

## Reference(s):

Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 214.