Practice question

**Energy transfer** first law ΔU = Q - W, W includes P-V work, shaft work, electrical work, Q includes conduction Fourier law, convection, radiation Stefan-Boltzmann, distinction important because work is controllable, heat spontaneous from hot to cold, entropy associated with heat not work, explaining why heat engine efficiency <100%. W = P Δ V , P V = μ R T . Δ V = 14 - 7 = 7 L . P = (μ R T)/(V₁) = (1.1 × 8.3 × 390)/(7) = 509.01 atm (unit correction needed).Directly: W = μ R T ((V₂ - V₁)/(V₁)) , but W = P Δ V .