C

Charles's Law

V₁/T₁ = V₂/T₂ (at constant P and n); V/T = k
Quick Reference
Formula / NotationV₁/T₁ = V₂/T₂ (at constant P and n); V/T = k
Also Known AsVolume-temperature law, Gay-Lussac-Charles law, isobaric gas law

What is Charles's Law?

Charles's Law states that at constant pressure, the volume of a fixed amount of ideal gas is directly proportional to its absolute temperature (V ∝ T, or V/T = constant). First published by Jacques Charles in 1787, it describes the thermal expansion of gases. Combined with Boyle's Law, it forms part of the ideal gas law (PV = nRT).

Formula & Notation

V₁/T₁ = V₂/T₂ (at constant P and n); V/T = k

Other Names / Synonyms: Volume-temperature law, Gay-Lussac-Charles law, isobaric gas law

Properties & Characteristics

Charles's law states that the volume of a fixed mass of gas at constant pressure is directly proportional to its absolute temperature (in Kelvin): V ∝ T, or V/T = constant. Established by Jacques Charles (1787) and verified by Gay-Lussac, it predicts that gases contract as temperature decreases and that volume would theoretically reach zero at absolute zero (−273.15°C). Real gases liquefy before this is reached.

Uses & Applications

Charles's law explains the behaviour of hot air balloons, explains why tyre pressure and volume change with temperature, and is used in engineering calculations for gas-handling equipment. Combined with Boyle's law and Avogadro's principle, it leads to the ideal gas law PV = nRT.

Safety Information

Gases in sealed containers (aerosol cans, compressed gas cylinders) experience pressure increases when heated — a fire and explosion hazard described by the combined gas law. Never heat closed containers. Store compressed gases away from heat sources.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Charles's Law
Formula V₁/T₁ = V₂/T₂ (at constant P and n); V/T = k
Synonyms Volume-temperature law, Gay-Lussac-Charles law, isobaric gas law

Frequently Asked Questions

Charles's Law states that at constant pressure, the volume of a fixed amount of ideal gas is directly proportional to its absolute temperature (V ∝ T, or V/T = constant). First published by Jacques Charles in 1787, it describes the thermal expansion of gases. Combined with Boyle's Law, it forms part of the ideal gas law (PV = nRT).

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