That is, most processes that we're concerned with, they'll happen with something held constant like pressure or temperature or maybe volume.

这句话是说我们所关注的大部分过程，发生的时候都是保持某个量为常数,比如压强，温度或者体积。

麻省理工公开课 - 热力学与动力学课程节选

Hydrogen gas it's in its most stable state, right at room temperature and pressure.

和常压下氢气是氢元素，最稳定的状态，这个小“0“

麻省理工公开课 - 热力学与动力学课程节选

Now in this particular reaction, I've got hydrogen gas, iron solid. Those already are elements in their most stable forms at room temperature and pressure.

特定的反应中，我有氢气,固态铁，这些都已经是,处于室温和常压下,最稳定的元素单质。

麻省理工公开课 - 热力学与动力学课程节选

Delta H of formation means the enthalpy of this compound minus the enthalpy of its constituent elements in their most stable state at room temperature and pressure.

生成焓就是这种组分,的焓减去它的所有组成元素,在室温和常压下处于,其最稳定的状态时的焓。

麻省理工公开课 - 热力学与动力学课程节选

Iron as an element is a solid. That's it's most stable state at room temperature and pressure, right, and so on. And then we can figure out heats of formation.

铁单质是固态,这是他在室温和常压下,最稳定的状态，然后我们,可以算出生成热，现在这个。

麻省理工公开课 - 热力学与动力学课程节选