Entropy Change Calculator
Works out an entropy change. The fields for the other method are ignored.
Entropy change ΔS
— J/(mol·K)
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Products — J/(mol·K)
Reactants — J/(mol·K)
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The formula
ΔS = Σ n S°(products) − Σ n S°(reactants) ΔS = ΔH ÷ T at a phase change
T is in kelvin. Entropy is in joules per mole per kelvin, while enthalpy is usually in kilojoules.
What to watch out for
The default values are CaCO₃ → CaO + CO₂. Making a gas from a solid brings a large rise in entropy.
Frequently Asked Questions
What is ΔS for the decomposition of calcium carbonate?
Using 39.7, 213.7 and 92.9 J/(mol·K): 160.5 J/(mol·K).
What is the entropy of vaporisation of water?
With ΔH of 40.7 kJ/mol at 100 °C: 109.1 J/(mol·K).