Practice question

**Partial pressure concept** for mixture of non-reacting gases, total pressure sum of partials, each gas behaves independently, kinetic theory still holds with effective n = Σ n_i, mean free path depends on total n and cross-sections, mixture properties weighted by mole tions. v_rms ∝ (1)/(√(m)), v_O₂v_He = √(m_He)m_O₂.v_O₂1370 = √((4)/(32)) = √(0.125) ≈ 0.3535.v_O₂ = 1370 × 0.3535 ≈ 484 m/s. Substituting values gives 484 m/s, which matches expected kinetic theory result, confirming mean free path λ = 1/(√2 n π d²), ideal gas law P V = n R T and v_rms = √(3 R T/M) relations.