Colligative properties are the properties like the vapor pressure lowering when you have a mixture in a liquid instead of having a pure substance you have amixture of substances here .

依数现象是这样一种现象，当你把物质混合在一起的时候，你不会得到纯物质，而是得到混合物质。

And we also drew a phase diagram to show how this vapor pressure lowering was going to imply freezing point depression and boiling point depression .

我们来画相图， 蒸汽 压 下降，意味着凝固点降低，和沸点降低。

There is vapor pressure lowering .

蒸汽 压 的 下降。

And the first thing that you can use this for is to look at your first colligative property which is vapor pressure lowering .

你可以利用这个定律的第一个地方，是我们的第一个依数效应，在这个效应中 蒸汽 压 下降。

It 's going to come from the vapor pressure lowering not from the osmotic pressure which we 'll do next .

我们可以从 蒸汽 压得变化，而不是渗透压，得到这个结果。