All right, let's take the example of, the extreme example, let's go to the extreme example where p external is really small.

好了，现在我们来，看一个，极限情况,当外界压强非常小。

麻省理工公开课 - 热力学与动力学课程节选

The property is the limit as p goes to zero of pressure times molar volume.

与摩尔体积的乘积,在气体压强p趋于0时的极限。

麻省理工公开课 - 热力学与动力学课程节选