## SO3 (g) + 1 H2O (ℓ) → H2SO4 (aq)

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## Stoichiometry

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 SO3            Mass: g or Gas Volume: L H2O            Mass: g H2SO4          Mass: g Heat Released: kJ

## Enthalpy of Reaction

[1ΔHf(H2SO4 (aq))] - [1ΔHf(SO3 (g)) + 1ΔHf(H2O (ℓ))]
[1(-909.27)] - [1(-395.72) + 1(-285.83)] = -227.72 kJ
-227.72 kJ     (exothermic)

## Entropy Change

[1ΔSf(H2SO4 (aq))] - [1ΔSf(SO3 (g)) + 1ΔSf(H2O (ℓ))]
[1(20.08)] - [1(256.65) + 1(69.91)] = -306.48 J/K
-306.48 J/K     (decrease in entropy)

## Free Energy of Reaction (at 298.15 K)

From ΔGf° values:
[1ΔGf(H2SO4 (aq))] - [1ΔGf(SO3 (g)) + 1ΔGf(H2O (ℓ))]
[1(-744.63)] - [1(-371.08) + 1(-237.18)] = -136.37 kJ
-136.37 kJ     (spontaneous)

From ΔG = ΔH - TΔS:
-136.34 kJ     (spontaneous)

## Equilibrium Constant, K (at 298.15 K)

7.8040444231e+023
This process is favorable at 25°C.

## Reference(s):

Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; pp 217, 303.