例5 2 mol的N2 (设为理想气体)处于300K,101.325kPa的始态,经下列-|||-不同过程后使压力降半,分别求算各过程中的功:-|||-(1)向等体积的真空自由膨胀;-|||-(2)对抗恒外压 .5times 101.325kPa 等温膨胀;-|||-(3)等温可逆膨胀;-|||-(4)绝热可逆膨胀;-|||-(5)绝热对抗恒外压 .5times 101.325kPa 膨胀;-|||-(6)沿着 (V)^0.5= 常数的可逆多方过程;-|||-(7)沿着 = 常数的可逆多方过程;-|||-(8)沿着 VT= 常数的可逆多方过程;-|||-(9)沿着 -P 图中T1,p1(300K,101.325 kPa)到T2,P 2(240K,0.5×-|||-101.325kPa)的直线可逆膨胀。