Density

Density and Gas Properties

• The equation for density is mass per unit volume (ρ = m/V).

Mass and Volume Measurement

• The standard metric units for mass are grams (g) or kilograms (kg).
• Volume is typically measured in cubic meters (m³) or liters (L).

Calculating Density of Gases

• Gases are more difficult to compute density for because their molecules are widely spaced, making it harder to measure their volume accurately.
• The density of a gas is calculated using the ideal gas law equation.

Ideal Gas Law Equation

• The ideal gas law equation is PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature in Kelvin.
• In the ideal gas law equation, the variable R represents the gas constant (approximately 8.3145 J/mol·K).

Modifying Ideal Gas Law for Density

• To introduce the density parameter, the ideal gas law equation can be modified to PV = mRT/M, where M is the molar mass of the gas.
• The formula for the molar mass of a substance is the sum of the atomic masses of its constituent atoms.
• The ideal gas law equation can be modified to calculate the density of a gas by rearranging the equation to density (ρ) = m/V = PM/RT.