If you have a quantity which is constant over any closed path, that quantity is a thermodynamics state function.
如果有一个物理量,对任何闭合回路积分是常数,这个物理量就是一个热力学态函数。
So for the reversible process, the work done is the integral under the pressure volume state function, the function of state.
对可逆过程,做的功,是压强体积态函数曲线下,的积分面积。
Then we can also talk about the 2, 1, 0 state function, psi2 1 0 which would be psi 2, 1, 0.
我们也可以看看,2,1,0态波函数,它是。
All right, so this is the heat flowing in or out of the system, and these are all functions of state.
好的,这就是系统的热量变化,这些都是态函数。
And the equation of state, pressure versus volume at constant temperature, is going to have some form, let's just draw it in there like that.
系统的态函数,恒温下压强比体积,变化曲线,就像这样。
are all functions of state and parameters that we can control like temperature and pressure.
公式里面的全部都是态函数,我们控制态函数的参数比如温度或者压强。
It's a state function, so we're at constant temperature and pressure, and now we want to consider some chemical change or a phase transition or you name it.
这就是态函数,我们处于恒定的温度和压强之下,然后考虑某些化学变化或者相变,或者你想考虑的东西。
You need a functional form that connects the value at one state of matter, the freezing point of water to another phase change, the boiling point of water.
你需要一个函数形式来,连接物质某个态对应的温度值,如水的冰点,和另一个相变,如水的沸点。
OK, so, the thing about a state function is that the function has a value for initial conditions and at final conditions.
态函数的特点是,在初始状态有一个值,在末状态也有一个值。
It's a state function. If we know the enthalpy of the products minus the enthalpy of the reactants, right. It's a state function.
如果我们知道生成物的焓减,去反应物的焓的值,它是个态函数,原则上我们可以做到。
But since these are all simply state functions and quantities, this is generally true.
但是因为这些量都是态函数或者量,所以这个结果是普遍成立的。
This is only defined in terms of state functions.
但是他们只是态函数。
They only depend on the state the system is in.
态函数是不变的,它们只依赖于。
And we're actually going to get a little bit deeper in our clicker questions here, since when you do your problem-set it won't be quite this straight forward that you'll be answering this kind of question, but actually you'll be thinking about how many different orbitals can have certain state functions or certain orbital names.
事实上我们要讲的,比这个问题还要深一些,因为当你们做习题集的时候,你们不会遇到这么明显的问题,而是要考虑有多少个轨道,有某种特定的态函数,或者特定的轨道名字。
Delta u, delta H, familiar state functions, q w changes in their values, q, w, heat and work.
U,△H,很熟悉的态函数,它们的值在变化;
Now remember, we went through before how it's a state function but to calculate it, you'd need to find a reversible path, along which you can figure this out.
请记住,我们不需要知道它是怎样的一个态函数,只计算就可以了,你需要找到一条可逆路径,沿着这条路径就能算得这个结果。
But the fact is it's a state function, in a general way.
事实上这也是个态函数,是普遍成立的。
There's no change in them, and then we also looked at some at non-state functions, work and heat, and saw that those aren't zero going around a cycle. Of course you can do work in a cyclic process, and heat can be exchanged with the environment at the same time.
它们不会有变化,然后我们研究了,一些非态函数,功和热量,并看到,沿着循环行进一周的话,它们并不是零,当然你可以在,一个循环过程中做功,而同时热量可以在系统,与外界环境之间进行交换。
Since these are all state functions.
因为所有的热力学量都是态函数。
So that's an equation of state.
所以它是态函数。
Anybody have an idea? What's the one function of state? I'm the system, the rest are the surrounding. What's the one function of state that's constant when I'm doing all my chemical reactions to move my arms around?
态函数又是什么呢?,我是一个系统,其余的是周围的环境,那么当我在做所有的化学反应,去四处移动我的手臂的时候,什么量是常数?
So we'd really like to be able to find some sort of equation of state, or some sort of rather function of state that's going to relate the heat going in or out of the system with that function of state, because this isn't going to do it.
所以我们真的想要去,找到一些态方程或者态函数,通过这个态函数可以表示热量,在系统与外界的交换,因为这个不能表示它。
Therefore, from experiments, u is only a function of temperature for an ideal gas, H and therefore from these experiments, 0 we come out with delta H dH/dp is equal to zero.
因此,从实验可以得出,对于理想气体u只是温度的态函数,因此从这些实验中我们得到Δ,偏H偏p等于。
So what does that tell us about a state function like u?
所以这告诉我们的是,这过程中像u这样的态函数式怎么变化的?
And of course, in either case, w delta u is q plus w, so it's q irreversible plus w irreversible, u being a state function it's the same in either case.
当然了,在这两个过程中,Δu都等于q加,因此现在是q不可逆加w不可逆,同时u在这两个过程中都是态函数。
We should be able to calculate delta H.
应该能计算△H,它是个态函数。
And it's more dramatic if the system is a gas p T2 V2 p, T2, V2, And let's look at what happens to U these functions of state, to H to u under this transformation.
如果是气体这个系统,就更具有趣了,让我们看看H和,在这个变化中态函数会发生什么变化。
Cv The only difference is it'll be Cp instead of Cv, B but there it is for pathway B. There it is for C a pathway C. So the state functions that we're familiar with are doing what we expect they ought to be doing, right? If you go around in a cycle, starting and ending at the same place the state functions have to stay the same.
是Cp而不是,这是路径,这是路径,所以我们熟悉的态函数的行为,正与我们预期的相同,对吧?,如果你沿着循环走一圈,开始和结束于同一个位置。
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