Entropy Change Calculator
Calculate the change in entropy (ΔS) when a substance is heated or cooled at constant pressure, based on its mass, specific heat capacity, and temperature change.
What this calculator finds
Entropy (S) is a measure of the disorder or energy dispersal in a system. When a substance is heated or cooled at constant pressure without changing phase, its entropy change can be calculated from its mass, specific heat capacity, and the ratio of its final and initial absolute temperatures.
The formula used
This calculator uses the standard thermodynamic relationship for heating or cooling at constant pressure: ΔS = m × c × ln(T2 / T1), where m is mass, c is specific heat capacity, and T1 and T2 are the initial and final temperatures in Kelvin. Temperatures you enter in °C are automatically converted to Kelvin before the calculation.
- A positive ΔS means entropy increased (typically heating).
- A negative ΔS means entropy decreased (typically cooling).
This calculator assumes no phase change occurs between the initial and final temperature (no melting, freezing, or boiling), since a phase change contributes an additional entropy term. It is intended for general chemistry education and planning purposes.