Gas Pressure Calculator
Calculate gas pressure using P = nRT/V or P = ρRT/M for ideal gases.
What Is Gas Pressure Calculator?
This calculator implements Calculate gas pressure using P = nRT/V or P = ρRT/M for ideal gases. — a core relationship in physics.
The formula follows from fundamental principles and applies across a wide range of physical scenarios.
Pay attention to units and sign conventions when using these calculations in practice.
Results are valid within the stated assumptions; real systems may deviate at extremes.
Formula Reference Table
| Solve For | Formula | Notes |
|---|---|---|
| Ideal gas law | P = nRT/V | R = 8.314 J/(mol·K) |
| From density | P = ρRT/M | ρ = density, M = molar mass |
| Moles from PV | n = PV/(RT) | |
| STP condition | P=100 kPa, T=273.15 K | 1 mol = 22.4 L |
| Boyle's Law | P₁V₁ = P₂V₂ | At constant T, n |
| Gay-Lussac | P₁/T₁ = P₂/T₂ | At constant V, n |
3 Worked Examples
n=1 mol, T=273.15 K, V=22.414 L=0.022414 m³.
- P = nRT/V = 1×8.314×273.15/0.022414 = 101,322 Pa ≈ 1 atm ✓
Tire: n=0.5 mol, V=0.01 m³. Cold (15°C=288 K) P=220 kPa. Hot (50°C=323 K)?
- P₂ = P₁T₂/T₁ = 220,000×323/288 = 246,736 Pa = 246.7 kPa
- Pressure rises 12% — check tires when cool
Air: ρ=1.225 kg/m³, T=293 K, M=0.029 kg/mol.
- P = ρRT/M = 1.225×8.314×293/0.029 = 103,027 Pa ≈ 1 atm ✓
Real-World Applications
Common Mistakes to Avoid
SI units.
Correct variant.
Ideal conditions.
Check conventions.
Check squaring.
Frequently Asked Questions
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Interpretation: This relationship connects pressure, velocity, density, viscosity, geometry or transport in a fluid system. Assumption: Check whether flow is steady, incompressible, laminar, fully developed or one-dimensional. Reynolds and Mach regimes determine whether simplified formulas are valid.