Thermodynamics: One-Page Formula Sheet

Thermodynamics — formula sheet

Formulas

• Isothermal: W = nRT ln(V₂/V₁)
• Adiabatic: PVᵞ = constant, W = (P₁V₁ − P₂V₂)/(γ − 1)
• Cₚ − Cᵥ = R
• Carnot efficiency η = 1 − T₂/T₁

Key ideas

• First law: Q = ΔU + W (W = work done by the gas)
• Internal energy of an ideal gas depends only on temperature
• Work = area under the P–V curve
• No engine is more efficient than a Carnot engine between the same temperatures

Traps to avoid

• Sign convention mix-up between physics (W by gas) and chemistry books
• Using Celsius instead of kelvin in efficiency
• Forgetting ΔU = 0 only for a complete cycle or isothermal ideal gas

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