Gas laws · Grade 11
The pressure, volume and temperature of a fixed amount of gas are linked. Squeeze a gas and its pressure rises; heat it and it pushes harder or expands. These gas laws only work neatly when temperature is measured in kelvin, from absolute zero.
Key facts
- Temperature in kelvin: K = °C + 273. Absolute zero is 0 K = −273°C.
- Boyle’s law (constant T): p₁V₁ = p₂V₂.
- Charles’s law (constant p): (V₁)/(T₁) = (V₂)/(T₂).
- Pressure law (constant V): (p₁)/(T₁) = (p₂)/(T₂).
- Combined: (p₁V₁)/(T₁) = (p₂V₂)/(T₂).
- Ideal gas equation: pV = nRT = NkT (R = 8.31 J/(mol K), k = 1.38 × 10⁻²³ J/K).