Practice question

**Internal energy** state function depends only on temperature for ideal gas, U = f/2 n R T, change ΔU = n C_v ΔT, first law connects heat, work, internal energy, for expansion work done by gas positive, compression work done on gas negative, heat added positive. First Law: Δ Q = Δ U + Δ W . Δ Q = 450 , Δ W = 150 . 450 = Δ U + 150 ⇒ Δ U = 450 - 150 = 300 J . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W =