That tells us the direction of spontaneous change for ordinary processes, chemical processes, mixing and you name it, under conditions that are easy to achieve in the lab.

这个物理量告诉我们在实验室,能够实现的条件下通常的过程，化学过程，混合以及你所能想到的过程，自发进行的方向。

麻省理工公开课 - 热力学与动力学课程节选

Of course, they're all sorts of conditions under which a reaction could be wrong in the lab or outdoors or however, right. But this is the way we're going to define delta H of reaction.

当然，在实验室或室外,之类的环境中，在这些条件下,反应可能出错，但这是我们,要定义反应的△H的方法。

麻省理工公开课 - 热力学与动力学课程节选