Gibbs Free Energy Calculator

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Choose what you want to calculate. Each mode rearranges the Gibbs equation or uses a related formula.
Absolute temperature. 25 °C = 298.15 K = 77 °F.
Heat released (negative) or absorbed (positive) by the reaction at constant pressure.
Entropy change per mole per kelvin. Tabulated values are usually in J/(mol·K).
Gibbs free energy (ΔG)Spontaneous (ΔG < 0)
-32.958kJ/mol
Gibbs free energy (ΔG)-32,957.6J/mol
Entropy term (T·ΔS)-59.242kJ/mol
Crossover temperature (T = ΔH/ΔS)464.02K
Crossover temperature190.87°C
-32.958 kJ/mol
Strongly spontaneous<-100Spontaneous-100--10Weakly spontaneous-10-0Near equilibrium0-10Non-spontaneous10-100Strongly non-spontaneous100+

ΔG = -32.958 kJ/mol: the reaction is spontaneous in the forward direction.

  • A negative ΔG means the forward reaction releases free energy and can proceed without outside work.
  • Spontaneous describes thermodynamic direction and feasibility, not reaction speed; a favourable reaction can still be very slow.
  • Spontaneity flips at the crossover temperature of 464 K (190.9 °C).

Next stepCheck whether the activation energy (kinetics) is low enough for the reaction to be fast at your temperature.

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