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So what they do is, they're describing how these thermodynamic properties change, in terms of only state functions and state variables.
他们的作用是描述,随着状态函数和状态变量的变化，系统的热力性质如何变化。
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Now the first law is going to hold in all of these steps, and we're going around in a cycle.
现在热力学第一定律,就蕴含在这所有的步骤里了，我们沿着这个循环走。
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So, what we're going to do now is look at the energetics associated with that.
所以现在我们要做的就是,看一下与之相关的热力学。
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And if you work out the energetics as we've gone with thermochemistry, dH you discover there's a huge negative delta H.
如果你计算能量变化,就像在化学热力学中所作的一样，你会发现很大的负的。
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So we're going to go through a thermodynamic cycle, and here's what I want to calculate when we do this.
那么我们要推导,一个热力学循环,这是这个过程中我要计算的东西。
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So in some sense, the first law would suggest you can sort of break even.
初看起来，热力学第一定律,可以保证这个过程是可行的。
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You know, we've done a bunch of thermochemistry, and we've kind of seen that the energy of mixing, your energetics don't change too much as a function of temperature.
我们做过很多的化学热力学习题，某种程度上我们发现混合的能量，并不随着能量,发生大的改变。
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Now, last day, we looked at the energetics of the ionic bond, right?
昨天，我们讲的是离子键的热力学，对么？
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Thermodynamicstalks about equilibrium systems and how to go from one state of equilibrium to another state of equilibrium.
热力学研究的是平衡系统,以及如何,从一个平衡态转变到另一个平衡态。
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So now let's go around the cycle and just compare notes on what happens to the thermodynamic quantities as we do that.
现在让我们推导一下这个循环,比较一下这个过程中,热力学性质的变化。
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And the bigger lesson from that is that entropy, unlike energy u or enthalpy H, we could define an absolutely number for it.
热力学第三定律的一个更重要的推论是,与内能和自由焓不同，我们可以给上定义一个绝对的数值。
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So thermodynamics, based on these four laws now, requires an edifice, and it's a very mature science, and it requires that we define things carefully.
热力学是一座，建立在这四条定律上的大厦,它是一门非常成熟的科学，也要求我们在定义东西时非常小心。
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This is an abstract and powerful mathematical statement of the first law of thermodynamics.
这是热力学第一定律的一个抽象,而且具有很强数学性的表述。
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And we can do that by going through and deriving What we'll call the fundamental equations of thermodynamics.
通过推导,所谓的,基本热力学方程可以做到这一点。
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So, thermo is also a big tease, as you can see from my descriptions of these laws here.
因此，热力学也是个大玩笑，从我下面对,这些定律的描述。
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It's not going to be zero this time because we have non zero heat exchange between the system and the environment, right.?
热力学量，但是现在让我们看一下,我们的特殊函数，这次它不会是零,因为系统与外界的热量交换并不是零，对吧？
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So, over the last few lectures we've worked and struggled so formulate the second and third laws of thermodynamics in addition to the first.
在前几次课中,我们通过努力明确的,给出了热力学,第一，第二和第三定律。
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Fairly powerful statement, and that's another form of the first law of thermodynamics.
这是一个相当有用的表述,是热力学第一定律的另外一种形式。
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We could choose any two quantities, and, in fact, it turns out that these are going to prove, after we have the second law, not to be the best choice.
我们可以任选两个物理量，其实，在学习了热力学第二定律之后，我们可以证明，这样的选择并不是最好的。
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That's for a different lecture So, anyway, thermodynamics dates from the same period as getting fossil fuels out of the ground. It's universal.
这是另一堂课的内容,不管怎么说,热力学与开采化石燃料,起源于同一时期，它是普适的。
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and added a structure of math upon it, to build this edifice, which is a very solid edifice of thermodynamics as a science of equilibrium systems.
了这座热力学的坚固大厦，这是一门，平衡态系统,的科学。
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And this is just an incredibly important area that thermodynamics allows us to speak to.
这是热力学中我们需要讨论的一个,很重要的领域。
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That is, it gives us the relationship between energy and work and heat.
热力学第一定律阐述了,能量，功和热之间的关系。
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It turns out that when you're talking about macroscopic properties of matter, you don't need very many variables to describe the system completely thermodynamically.
实际上,当你谈及物质的宏观性质时，你并不需要很多变量才能从热力学上,完整地描述这个系统，’
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So it applies to macroscopic systems that are in equilibrium, and how to go from one equilibrium state to another equilibrium state, and it's entirely empirical in its foundation.
因此，热力学研究的是平衡态的宏观系统,以及如何从,一个平衡态过渡到另一个平衡态，它完全是建立在经验的基础上的。
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So now, I want to take a look at the energetics of that.
现在我想看一下关于这个的热力学知识。
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now let's go back to each of our individual steps and look, based on what we know about how to evaluate the thermodynamic changes that take place here, let's look at each one of the steps and see what happens.
让我们回到循环中的每一步,然后看看，基于我们已有的知识,来估计一下,发生的热力学变化，让我们看,循环中的每一步发生了什么。
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So what we're going to do is consider the first and second laws.
我们需要考虑的是,热力学第一和第二定律。
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in the last couple lectures at a really important topic in thermodynamics.
在前面几次课里,面我们考察了热力学中一个很重要的课题。
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So you know, what the second law is doing, in other words, it's putting these restrictions on how well or how effectively we can convert heat into work in the case of the engine, or work into heat extracted in the case of a refrigerator.
你们知道，在热机中，热力学第二定律的作用，换句话说，就是给热量,转化为功的效率,施加限制,或在制冷剂中，对抽取热量,进行限制。
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