Gas Density Calculator
Calculate gas density using the ideal gas law with pressure, temperature, and molar mass
Calculate Gas Density
Gas pressure (standard atmospheric pressure = 101,325 Pa)
Gas temperature (standard temperature = 273.15 K = 0°C)
Molecular weight of the gas in grams per mole
Gas Density Results
Formula used: ρ = (M × P) / (R × T)
Conditions: P = 1,01,325 Pa, T = 293.15 K, M = 28.97 g/mol
Gas constant: R = 8.314462618 J⋅mol⁻¹⋅K⁻¹
Selected gas: Air (Dry)
Comparison with Air
Relative to air at STP: 0.932x
This gas is 1.07 times lighter than air
Gas Properties Analysis
Example Calculation
Carbon Dioxide at Standard Conditions
Gas: Carbon Dioxide (CO₂)
Molar Mass (M): 44.01 g/mol
Pressure (P): 101,325 Pa (1 atm)
Temperature (T): 273.15 K (0°C)
Calculation
ρ = (M × P) / (R × T)
ρ = (0.04401 kg/mol × 101,325 Pa) / (8.314 J⋅mol⁻¹⋅K⁻¹ × 273.15 K)
ρ = 4,459.33 / 2,271.1
ρ = 1.964 kg/m³
CO₂ is about 1.96 times denser than air!
Common Gas Densities (STP)
* At Standard Temperature and Pressure (STP): 0°C, 1 atm
Ideal Gas Law
Gas Density Tips
Higher pressure increases gas density
Higher temperature decreases gas density
Heavier molecules have higher density
STP conditions: 0°C, 1 atm pressure
Ideal gas law applies to most gases at moderate conditions
Understanding Gas Density
What is Gas Density?
Gas density (ρ) is the mass of gas per unit volume, typically expressed in kg/m³ or g/L. Unlike solids and liquids, gas density varies significantly with temperature and pressure, making it a dynamic property that depends on environmental conditions.
Factors Affecting Gas Density
- •Pressure: Higher pressure compresses gas molecules closer together, increasing density
- •Temperature: Higher temperature causes gas expansion, decreasing density
- •Molar Mass: Heavier molecules result in higher density at same conditions
- •Humidity: Water vapor affects the effective molar mass of air
Ideal Gas Law Derivation
Start with: PV = nRT
Where: n = m/M (moles = mass/molar mass)
Substitute: PV = (m/M)RT
Rearrange: PVM = mRT
Solve for m/V: m/V = PM/RT
Since ρ = m/V: ρ = PM/RT
Applications
- Weather Prediction: Air density affects barometric pressure
- Aviation: Aircraft performance depends on air density
- Industrial Processes: Gas flow calculations and storage
- Environmental Monitoring: Pollutant dispersion modeling
- Safety: Determining if gases will rise or sink