I mean that's obvious. The mass, if you double the amount of stuff the mass will double.

这是显然的，还有质量，如果你把系统中物质的,数量增加一倍，质量也会增加一倍。

麻省理工公开课 - 热力学与动力学课程节选

You just need a few macroscopic variables that are very familiar to you, like the pressure, the temperature, the volume, the number of moles of each component, the mass of the system.

你只需要某些你非常熟悉的宏观变量,比如压强，温度，体积，每个组分的摩尔数，系统的质量。

麻省理工公开课 - 热力学与动力学课程节选

He goes back and redoes the calculation, only in this case he says what I am going to do is I am going to redo the calculation for helium, but I am going to consider not just the mass of the electron but the reduced mass of the system.

他回去重新做了计算，仅在这种情况下他才会说说我将要,为氦重做计算，但我认为,不只是电子的质量,还有系统质量的减少量。

麻省理工公开课 - 固态化学导论课程节选