⏱️ Kinetics & Thermochemistry

4 calculators in this category.

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Calculators for reaction rates and energy changes: radioactive and first-order half-life, rate constants, the effect of temperature by the Arrhenius equation, and spontaneity from Gibbs free energy.

Calculate how much of a radioactive substance (or first-order reactant) remains after a given time from its half-life: N = N₀ × (½)^(t/t½). Also gives the decay constant.

First Order Rate Constant

Calculate the rate constant k of a first-order reaction from the initial and remaining concentration and the time, k = (2.303/t) log([A]₀/[A]), plus the half-life.

Arrhenius Equation

Use the Arrhenius equation to find the rate constant at a new temperature from the rate constant at one temperature and the activation energy: log(k₂/k₁) = Ea/2.303R (1/T₁ − 1/T₂).

Gibbs Free Energy

Calculate the Gibbs free energy change ΔG = ΔH − TΔS to see whether a reaction is spontaneous, plus the equilibrium constant K from ΔG° = −RT ln K.