Ideal Gas Density Calculator

This calculator is rooted in the rearranged Ideal Gas Law equation: ρ = (M × P) / (R_u × T), where ρ represents density, M is the molar mass of the gas, P is absolute pressure, R_u is the universal gas constant (8.314 J/(mol·K)), and T is absolute temperature measured in Kelvin. By substituting moles per volume with mass per volume, the classic equation PV = nRT transforms into a direct relationship between a gas's physical state variables and its spatial mass distribution.

Let us calculate the density of oxygen gas (O₂) at a pressure of 150 kPa and a temperature of 300 K. First, identify the molar mass of oxygen, which is approximately 0.032 kg/mol. Next, use the universal gas constant R_u = 8.314 J/(mol·K). Applying the formula: ρ = (0.032 kg/mol × 150,000 Pa) / (8.314 J/(mol·K) × 300 K). Multiplying the numerator yields 4,800, while the denominator yields 2,494.2. Dividing these values gives a density of approximately 1.924 kg/m³.

Always convert your temperature inputs to Kelvin (K) and pressure to Pascals (Pa) or atmospheres consistently before running calculations to avoid severe magnitude errors. Remember that the ideal gas law assumes point-mass molecules with no intermolecular forces, meaning calculations for gases at extremely high pressures or near their condensation points will diverge from real-world experimental results.