Activation Energy Calculator
Calculate activation energy using the Arrhenius equation with two-temperature rate data. Supports Ea from rate constants, frequency factor estimation, and temperature dependence analysis.
Free Thermochemistry Calculators
9 toolsEnthalpy, entropy, Gibbs energy, and reaction energy calculators. Browse our free thermochemistry tools below — no sign-up required.
Arrhenius Equation Calculator
Solve the Arrhenius equation for rate constant, activation energy, frequency factor, or temperature. Includes Arrhenius plot data and multi-temperature analysis.
Combustion Analysis Calculator
Determine empirical and molecular formulas from combustion analysis data. Enter masses of CO₂ and H₂O produced to find percent composition and molecular formula.
Combustion Reaction Calculator
Calculate heat released, oxygen required, and products formed in combustion reactions. Supports hydrocarbons, alcohols, and custom organic fuels with complete/incomplete combustion.
Entropy Calculator
Calculate entropy change for chemical reactions, phase transitions, and mixing processes. Covers ΔS°rxn from standard molar entropies and Boltzmann entropy.
Equilibrium Constant Calculator
Calculate equilibrium constant Kc, Kp, and reaction quotient Q. Determine equilibrium concentrations, predict reaction direction, and convert between Kc and Kp.
Gibbs Free Energy Calculator
Calculate Gibbs free energy (ΔG) from enthalpy and entropy, determine spontaneity, and find equilibrium temperatures. Supports ΔG°rxn from formation data and ΔG = ΔH - TΔS.
Heat of Combustion Calculator
Calculate standard enthalpy of combustion for fuels and organic compounds. Compare higher and lower heating values, energy density, and CO₂ intensity across fuels.
Rate Constant Calculator
Calculate reaction rate constants from experimental data for zero, first, and second order reactions. Determine reaction order, half-life, and rate law parameters.