Isothermal (Constant-Temperature) Processes of Ideal Gases in a Closed System
\(\displaystyle pV = \text{constant}\)
\(\displaystyle p_1 V_1 = p_2 V_2\)
\(\displaystyle V_2 = V_1\,\frac{p_1}{p_2} \qquad \text{and} \qquad p_2 = p_1\,\frac{V_1}{V_2}\)
Symbols
  • \(p\) — absolute pressure
  • \(V\) — volume
  • subscript \(1\) — initial state
  • subscript \(2\) — final state

Schematic

Isothermal piston-cylinder schematic

Inputs & Outputs

Final volume \(V_2\)
State 1: \(p_1,\;V_1\)
kPa,
State 2: \(p_2,\;V_2\)
kPa,
Constant \(p_1 V_1 = p_2 V_2\)
kPa·m³

Plot

The red dot marks the current final state. Drag it along the curve, or use the inputs above to change the final state.