Specific Gas Constant Calculator
Calculate the specific gas constant for gases using molar mass or specific heat capacities
Calculate Specific Gas Constant
Choose the method based on available data
Specific Gas Constant Results
Unit Conversions
Calculation Details
Gas Properties Analysis
Example Calculation
Air Properties
Method: Molar Mass
Molar Mass: 28.96 g/mol
Universal Gas Constant: 8.314 J/(mol·K)
Calculation
Rs = R / M
Rs = 8.314 / 0.02896
Rs = 287.1 J/(kg·K)
Specific gas constant for air
Formula Reference
Molar Mass Method
Rs = R / M
Universal constant / Molar mass
Specific Heat Method
Rs = Cp - Cv
Difference in heat capacities
Common Gas Values
Physics Tips
Higher Rs means lighter gas at same conditions
Rs is essential for ideal gas density calculations
Molar mass method is most common and accurate
Units must be consistent: use kg/mol for molar mass
Used in compressible flow and gas dynamics
Understanding Specific Gas Constant
What is Specific Gas Constant?
The specific gas constant (Rs) is the ratio of the universal gas constant to the molar mass of a gas. It represents the gas constant per unit mass and is essential for calculations involving gas density, compressible flow, and thermodynamic processes.
Physical Significance
- •Inversely proportional to molar mass
- •Higher for lighter gases (H₂, He)
- •Used in modified ideal gas law: P = ρRsT
- •Essential for gas density calculations
Calculation Methods
Method 1: Molar Mass
Rs = R / M, where R = 8.314 J/(mol·K) and M is molar mass in kg/mol. Most common and accurate method.
Method 2: Specific Heat
Rs = Cp - Cv, where Cp and Cv are specific heat capacities at constant pressure and volume respectively.
Note: Both methods should give identical results for ideal gases. Discrepancies may indicate non-ideal behavior or measurement errors.
Gas Classification by Specific Gas Constant
Light Gases (Rs > 1000)
- • Hydrogen: 4124 J/(kg·K)
- • Helium: 2077 J/(kg·K)
- • Low density, high buoyancy
- • Used in balloons, airships
Medium Gases (200-600)
- • Air: 287 J/(kg·K)
- • Nitrogen: 297 J/(kg·K)
- • Oxygen: 260 J/(kg·K)
- • Common atmospheric gases
Heavy Gases (Rs < 200)
- • CO₂: 189 J/(kg·K)
- • Butane: 143 J/(kg·K)
- • High density gases
- • Used in refrigeration
Applications of Specific Gas Constant
Gas Density Calculations
Calculate gas density using ρ = P/(Rs×T). Essential for HVAC design, gas storage, and pipeline engineering.
Compressible Flow
Analyze gas flow in nozzles, diffusers, and turbomachinery. Critical for aerospace and gas turbine applications.
Thermodynamic Cycles
Design and analyze gas turbine cycles, refrigeration systems, and heat pumps using gas-specific properties.