Second Law of Thermodynamics
| Formula / Notation | ΔS_universe > 0; ΔS_universe = ΔS_sys + ΔS_surr ≥ 0 |
|---|---|
| Also Known As | Second law, entropy law, law of entropy increase |
What is Second Law of Thermodynamics?
The law stating that in any spontaneous process, the total entropy of the universe increases (ΔSuniv > 0). Equivalently, heat flows spontaneously from hot to cold, and it is impossible to convert heat completely into work. This law defines the direction of spontaneous processes.
Formula & Notation
Other Names / Synonyms: Second law, entropy law, law of entropy increase
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The law stating that in any spontaneous process, the total entropy of the universe increases (ΔSuniv > 0). Equivalently, heat flows spontaneously from hot to cold, and it is impossible to convert heat completely into work. This law defines the direction of spontaneous processes.
The second law sets fundamental limits on the efficiency of heat engines and refrigerators (Carnot efficiency). It explains why chemical reactions reach equilibrium and guides industrial process optimisation. The second law underpins the entire framework of chemical thermodynamics and equilibrium.
The second law implies that energy dissipation and irreversibility are unavoidable. In engineering, it means that real processes always involve energy losses as heat, important for safety calculations involving thermal runaway.
The formula or notation for Second Law of Thermodynamics is: ΔS_universe > 0; ΔS_universe = ΔS_sys + ΔS_surr ≥ 0