Gibbs Free Energy Calculator
Find ΔG and whether a reaction is spontaneous.
Gibbs free energy predicts whether a reaction proceeds spontaneously.
How the Math Works
The Gibbs Free Energy Calculator uses the formula ΔG = ΔH − TΔS, where ΔG is the change in Gibbs free energy, ΔH is the enthalpy change, T is the absolute temperature in Kelvin, and ΔS is the entropy change. This equation combines enthalpy and entropy to determine the spontaneity of a reaction at constant temperature and pressure. A negative ΔG indicates a spontaneous process, while a positive value means the reaction is non-spontaneous. The calculator simplifies this calculation by allowing users to input values for ΔH, ΔS, and T, then automatically computes ΔG and its implications.
Practical Applications
To use this calculator, input the enthalpy change (ΔH) in joules or kilojoules, entropy change (ΔS) in joules per Kelvin, and the temperature in Kelvin. The calculator will compute ΔG and immediately display whether the reaction is spontaneous (ΔG < 0) or non-spontaneous (ΔG > 0). This tool is invaluable for chemists, engineers, and students analyzing reaction feasibility in laboratory experiments, industrial processes, or biological systems, such as predicting the efficiency of chemical synthesis or metabolic pathways.
Day-to-Day Use
Understanding Gibbs Free Energy helps explain everyday phenomena, from why ice melts at room temperature (spontaneous phase change) to the energy efficiency of batteries and fuel cells. It also aids in environmental science, such as predicting the spontaneity of chemical reactions in ecosystems or pollution breakdown. By applying this concept, individuals can better grasp energy transformations in technology, cooking, and even everyday decisions involving resource use and sustainability.
Worked example
ΔH −100, 298 K, ΔS 50 → ΔG −114.9 kJ/mol (spontaneous).
FAQ
ΔG = 0?
The reaction is at equilibrium.