Mayer's Relation (Cp - Cv = R)
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Cp - Cv = R
What each symbol means
| Symbol | What it stands for |
|---|---|
| R | Universal gas constant = 8.314 J mol⁻¹ K⁻¹ |
| C_p | Molar heat capacity at constant pressure (J mol⁻¹ K⁻¹) |
| C_v | Molar heat capacity at constant volume (J mol⁻¹ K⁻¹) |
When to use this
For ideal gas only. Cp > Cv because at constant P, gas expands doing extra work = PΔV = nRΔT → extra R per mole per K. γ = Cp/Cv = 1 + R/Cv. Monatomic: Cv = 3R/2, Cp = 5R/2. Diatomic: Cv = 5R/2, Cp = 7R/2.