Practice question

**Heat capacity** at constant pressure C_p and volume C_v, C_p = C_v + R per mole, for solids Dulong-Petit C_v≈3R≈25 J/mol·K. Specific heat and latent heat govern temperature changes and phase transitions, Q = m c ΔT for heating, Q = m L for melting/boiling at constant T. For isochoric process: Δ Q = μ C_v Δ T . Δ Q = 1000 , C_v = 20 , Δ T = 20 . 1000 = μ × 20 × 20 ⇒ μ = (1000)/(400) = 2.5 moles . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P