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Ideal gas equation
Beginner
Equation of state for ideal gases.
Key relation
PV = nRTPV = nRT = NkT, R = 8.314 J/mol·K. One mole at STP occupies 22.4 L.
Worked example
n = 2 mol at 300 K in 10 L: P = 5 atm approximately.
Common mistake
Use SI units.
In more detail
The ideal gas equation, PV = nRT, combines Boyle's, Charles's and Avogadro's laws. R is the gas constant, about 8.31 J/(mol K).
Real-world uses
- Chemical engineers design reactors and storage tanks using this equation.
- Meteorologists use it to relate air density to pressure and temperature.
- Chemists use PV = nRT to calculate the volume of gas produced in a reaction at a given temperature and pressure.
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Frequently asked questions
What is the gas constant?
About 8.31 J per mole per kelvin.
Can I use it for real gases?
Approximately, at moderate pressures and temperatures.
What is R?
The universal gas constant, about 8.31 joules per mole per kelvin, which connects the energy scale to the gas scale.
Related topics in Heat & Thermodynamics
Ideal gas laws · Boyle's law · Charles's law · Avogadro's number · Internal energy · First law of thermodynamics