But we've defined the enthalpy of those elements in their stable state at room temperature and pressure as zero, right?

但我们已经定义了这些,元素处于它们室温和常压下,最稳定的状态时的焓为零，对吧？

麻省理工公开课 - 热力学与动力学课程节选

What we define as zero is the enthalpy of every element in its natural state at room temperature and ambient pressure.

我们将零点定义为每种元素,在室温和正常大气压下,在其自然状态下的焓。

麻省理工公开课 - 热力学与动力学课程节选

If you have a large number of atoms in an aggregate, it is going to require that the substance turn solid and condense at room temperature.

如果有很多原子进行聚集，在室温下,会使的物质转变成固体状态。

麻省理工公开课 - 固态化学导论课程节选

And it's not hard to see how the heat of reaction at room temperature can be related to they heat of reaction at other temperatures.

知道室温下的反应热,如何与其他温度下的反应,热联系起来这点并不困难。

麻省理工公开课 - 热力学与动力学课程节选

And I didn't specify the conditions, but if we were to do this under ordinary chemical conditions of some, you'd say room temperature and pressure, right, they all happen spontaneously.

我并没有特别说明反应条件，但是如果我们在通常的化学条件下,实现这些化学反应，比如在室温和大气压下下，他们都是自发的。

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

Of course, it is evaporating like crazy because it is so warm in the room.

当然，它会剧烈的蒸发,因为室温温度很高。

麻省理工公开课 - 固态化学导论课程节选

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

We use a liquid helium. And so in order to make a liquid helium, you can't take helium at room temperature and do this, because if you did, you would just heat it up, because the room temperature is above the inversion temperature, so Joule-Thomson would heat up the helium.

为了得到液氦,不能再常温,做这个实验,否则就是加热氦气，因为室温高于它的转变温度,所以焦耳-汤姆孙，实验会加热氦气。

麻省理工公开课 - 热力学与动力学课程节选

Or in many kinds of gas refrigerators where you push a gas through a nozzle close to room temperature, what you find is that the gas coming out on the other side under lower pressure is cooler than the gas that went through on the other side.

或者在很多种压缩气体式冰箱中,你让气体通过接近室温的管口,你会发现从压力低的一边,出来的气体比通过,另一边的气体更冷,真正的冰箱实际上通过。

麻省理工公开课 - 热力学与动力学课程节选