What is the formula for work done by a gas in an isobaric process?

W = P × ΔV, where P is the constant pressure in pascals and ΔV = V₂ − V₁ is the change in volume in cubic meters. The result is in joules.

What is the formula for work in an isothermal process?

For an ideal gas at constant temperature: W = nRT × ln(V₂/V₁), where n is moles, R = 8.314 J/(mol·K), T is temperature in kelvin, and V₂/V₁ is the volume ratio.

Why is work zero in an isochoric process?

In an isochoric (constant volume) process, ΔV = 0, so W = P × 0 = 0 joules. No boundary work is done because the gas volume does not change.

What does a negative work value mean?

A negative value means work was done ON the gas (compression). The surroundings transferred energy into the gas, decreasing its volume.

What units should I use for input?

Use pascals (Pa) for pressure, cubic meters (m³) for volume, moles (mol) for amount of gas, and kelvin (K) for temperature. Common conversions: 1 atm = 101325 Pa; 1 L = 0.001 m³.

Work Done By Gas Calculator

Name: Work Done By Gas Calculator
Availability: InStock
Author: Nham Vu

Calculate the work done by a gas in isobaric, isothermal, or isochoric thermodynamic processes.

Gas Process Parameters

Thermodynamic Process

Constant pressure — W = P × (V₂ − V₁)

Pressure (Pa)

1 atm ≈ 101,325 Pa

Initial Volume V₁ (m³)

Final Volume V₂ (m³)

1 L = 0.001 m³ | 1 cm³ = 0.000001 m³

Result

Enter values and click Calculate.

Process Quick Reference

Isobaric W = P × (V₂ − V₁)

Isothermal W = nRT ln(V₂/V₁)

Isochoric W = 0

R = 8.314 J/(mol·K) — universal gas constant

Summary

Calculate the work done by a gas in isobaric, isothermal, or isochoric thermodynamic processes.

How it works

Select the thermodynamic process type: isobaric, isothermal, or isochoric.
Enter the required values for your chosen process.
Click Calculate to compute the work done by the gas.
Read the result in joules (J) and kilojoules (kJ).
A positive result means the gas did work on its surroundings (expansion); negative means work was done on the gas (compression).

Use cases

Solve thermodynamics homework problems involving gas expansion.
Verify manual calculations for isobaric or isothermal processes.
Understand the PV diagram area as mechanical work.
Compare work output across different process types.
Study heat engine cycles (Carnot, Otto, Diesel) step by step.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu