So, the formula for enthalpy is usually written as change in enthalpy.

因此，焓的公式通常写成焓变。

It's analogous to the standard enthalpy of formation that we use to calculate change in enthalpy.

类似于我们用来计算焓变的标准生成焓。

These measurements are done at standard conditions, which we discussed in the enthalpy and entropy episodes.

这些测是在标准条件下完成的， 我们在焓和熵情节中对此进行了讨论。

And I'm very happy the inventors knew how to calculate the enthalpy change of chemical reactions.

我很高兴发明者知道如何计算反应的焓变。

And we measure enthalpy with a weird little science called calorimetry.

我们用一种叫做热法的奇怪小科来测焓。

Why enthalpy change is different from heat, even though they turn out to be pretty much the same anyway.

为什么焓变与热不同， 尽管事实证明们几乎是一样的。

Those bonds are nothing but energy, and using enthalpy, we can measure how much energy they have.

这些键只不过是能， 使用焓，我们可以测们有多少能。

Change in enthalpy is equal to the heat gained or lost by the system.

焓变等于系统获得或损失的热。

The law itself says nothing about the standard enthalpy of formation.

定律本身并未提及标准生成焓。

So I guess in the capital H for enthalpy does kinda make sense.

所以我想在大写的 H 中表示焓确实有点道理。

So, I wonder how that compares to the amount we would predict using Hess's Law and the standard enthalpy of formation?

所以，我想知道这与我们使用赫斯定律和标准生成焓预测的相比如何？

Note that the standard enthalpy is in kilojoules while the standard entropy is in joules per Kelvin.

请注意，标准焓的单位是千焦耳， 而标准熵的单位是焦耳每开尔文。

Hess' Law is often stated in terms of standard enthalpies of formation.

赫斯定律通常用标准生成焓来表述。

As long as you start with the same reactants and end with the same products, the enthalpy change is the same.

只要您从相同的反应物开始并以相同的产物结束， 焓变就相同。

Thanks to many hardworking chemists, the standard enthalpy of formation has been measured for hundreds of compounds.

感谢许多辛勤工作的家，已经测了数百种物的标准生成焓。

First, we'll find the enthalpy change using Hess's Law and standard enthalpies of formation.

首先， 我们将使用赫斯定律和标准生成焓求出焓变。

Hopefully that sounds like fun because more about the ins and outs of this are coming in an episode on how to measure enthalpy.

希望这听起来很有趣，因为有关如何测焓的一集中将详细介绍这方面的来龙去脉。

A large change in enthalpy can determine the direction of a free energy change, even if the entropy changes in the opposite direction, and vice versa.

焓的大变可以决定自由能变的方向，即使熵的变方向相反， 反之亦然。

In order to study this stuff carefully, he looked at the standard enthalpies of formation of the reactants and the products of a reaction.

为了仔细研究这些东西，他研究了反应物和反应产物的标准生成焓。

When we plug the standard enthalpies of formation into the formula and do the math, we find that the change in standard enthalpy is plus 166 kilojoules.

当我们将标准生成焓代入公式并进行计算时，我们发现标准生成焓的变是加上 166 千焦耳。