Isothermal Process Calculator
Work from Volume Change
Calculate work done during isothermal expansion/compression from volume change
Work from Pressure Change
Calculate work done from initial and final pressures
Formula
W = nRT·ln(V₂/V₁) = nRT·ln(P₁/P₂) | Q = W | ΔU = 0 | PV = nRT = const
Frequently Asked Questions
What is an isothermal process?
An isothermal process occurs at constant temperature (ΔT = 0). For an ideal gas, this means internal energy does not change (ΔU = 0), so all heat absorbed equals the work done: Q = W = nRT·ln(V₂/V₁). Boyle's law (PV = const) applies.
How does isothermal differ from adiabatic?
Isothermal: temperature constant, heat exchanged freely (Q = W). Adiabatic: no heat exchange (Q = 0), temperature changes. Isothermal expansion does more work than adiabatic expansion from the same initial state because energy is continuously supplied as heat.
When does an isothermal process occur?
Isothermal processes occur when a system changes slowly enough to stay in thermal equilibrium with its surroundings, or when in contact with a large thermal reservoir. Examples include slow gas expansion in a cylinder surrounded by a water bath.
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