Isobaric Process Calculator
Enter moles, temperatures, pressure, and gas type to compute work done, heat transferred, and internal energy change for a constant-pressure process.
Process Inputs
Temperature unit
Pressure unit
Gas type
Cv = 2.5R, Cp = 3.5R
Enter values on the left and click Calculate.
Work (W)
—
J
—
Heat (Q)
—
J
—
ΔU
—
J
—
Initial Volume (V₁)
—
m³
Final Volume (V₂)
—
m³
Process Summary
T₁ (Kelvin)
—
T₂ (Kelvin)
—
ΔT
—
Pressure P
—
First law check (Q = ΔU + W)
—
Volume ratio V₂/V₁
—
Formulas:
W = nR(T₂ − T₁) | ΔU = nCvΔT | Q = nCpΔT | V = nRT/P
R = 8.314 J/(mol·K) | Monatomic: Cv = 1.5R, Cp = 2.5R | Diatomic: Cv = 2.5R, Cp = 3.5R
R = 8.314 J/(mol·K) | Monatomic: Cv = 1.5R, Cp = 2.5R | Diatomic: Cv = 2.5R, Cp = 3.5R
Summary
Enter moles, temperatures, pressure, and gas type to compute work done, heat transferred, and internal energy change for a constant-pressure process.
How it works
- Enter the number of moles (n) of the ideal gas.
- Set the initial temperature T₁ and final temperature T₂. Choose Kelvin or Celsius — the tool converts automatically.
- Enter the constant pressure P in Pascal (Pa) or kilopascal (kPa).
- Select the gas type: monatomic (Cv = 1.5R, Cp = 2.5R) or diatomic (Cv = 2.5R, Cp = 3.5R).
- The calculator outputs work W, heat Q, internal energy change ΔU, and initial/final volumes using V = nRT/P.
- Results update instantly. All outputs are rounded to 4 significant figures.
Use cases
- Solving first-law thermodynamics problems at constant pressure.
- Calculating heat added to or removed from a gas in an isobaric expansion or compression.
- Finding initial and final volumes via Charles's law (V₁/T₁ = V₂/T₂).
- Thermodynamics coursework on heat capacity ratios for monatomic and diatomic gases.
- Checking work done by a piston in a constant-pressure cylinder.
- Comparing energy exchanges in isobaric, isothermal, and adiabatic processes.
Frequently Asked Questions
Last updated: 2026-06-11 ·
Reviewed by Nham Vu