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。

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。

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

该定律本身并未提及标准生成焓。

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。

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化学家，已经测量了数百种化合物的标准生成焓。

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

它类似于我们用来计算焓变的标准生成焓。

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量相比如何？

The enthalpy change for a reaction is equal to the sum of the standard enthalpies of formation of the products, minus the sum of the standard enthalpies of formation of the reactants.

反应的焓变等于产物的标准生成焓之和减去反应物的标准生成焓之和。

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化是加上 166 千焦耳。

The standard enthalpy of formation for hydrochloric acid is -167.2 kJ per mole; for sodium hydroxide it's -469.15 kJ per mole; for liquid water it's -285.8; and for sodium chloride it's -407.27.

盐酸的标准生成焓为-167. 2 kJ/mol； 对于氢氧化钠，它是每摩尔 -469. 15 kJ； 对于液态水， 它是-285. 8； 对于氯化钠， 它是 -407. 27。

To define standard enthalpy of formation, I'm first going to define what a standard state is: Basically it's just a set of criteria so that chemists can all be studying stuff under the same conditions.

要定义标准生成焓， 我首先要定义标准状态是什么：基本上它只是一组标准，因此化学家都可以在相同条件下研究东西。

Remember that we can look up the standard enthalpy of formation for all the products and reactants in the back of a textbook or online, the chemical reaction between hydrochloric acid and sodium hydroxide produces liquid water and sodium chloride.

请记住， 我们可以在教科书后面或网上查找所有产品和反应物的标准生成焓，盐酸和氢氧化钠之间的化学反应生成液态水和氯化钠。