2)环境的熵变 △S环 Tswr T surr a)恒T可逆 b)恒T不可逆 2 Q=W,-nRTLn- △U=0W=0Q=0 V2 S环之4三nm应 △S环=0 T 17 17 2）环境的熵变 ΔS 环 = surr surr T Q = surr sys T − Q = Tsurr − Q a）恒 T 可逆 b）恒 T 不可逆 Qr =Wr =nRTLn 1 2 V V ΔU=0 W=0 Q=0 ΔS 环 = - T Qr = -nRLn 1 2 V V ΔS 环 = 0