This should be particularly bothersome to you because, as you've already experienced in 5.60, There are a lot of partial derivatives.
对你们来说这可能很让人头疼,就像你们在5。60里体验过的那样,这有很多偏微分和变量。
I can get better grades and you know, better average rather than going different uni, so.
我可以得到更好的成绩,中等偏上,比去其他大学要好。
So, all I want to do now is look at the derivatives of the free energies with respect to temperature and volume and pressure.
我现在所要做的一切就是,考察自由能对,温度,体积和压强的偏导数。
The baby is being approached, goes like this , smiles like this , and then the aversion .
有人走近这个婴儿,像这样,眉毛上挑凝视,开始微笑,像这样笑,大笑头偏向左,然后是讨厌的人,大笑头避开。
Little coffins, people were smaller then.
窄小的棺材,那时的人们身材偏小
Now when it reaches up to the right more towards the heart of that red zone, " 100 spikes per second.
现在,当它移动到,右上侧偏红色区域的时候,我们会听到嗑哩的声音,每秒钟100次,we,may,hear,“keri…
That is, it's easy to write down straight away that dG with respect to temperature at constant pressure S is minus S.
这就是说,可以很简单的写出dG在,恒定压强下对温度的偏导数,是负。
G We can take the derivative of G with respect to how much material there is.
我们可以取,对物质总量的偏导数。
When you say that, it implies that the differential is given by this pair of partial derivatives.
这就意味着,内能的微分,等于偏u偏T,保持体积不变。
We have discovered that this partial derivative that appears in the definition, the abstract definition of the differential for internal energy, is just equal to the constant volume heat capacity.
我们还发现,这个偏微分出现在了,内能的偏微分,定义式中,它也就是热容。
And then we can take the derivative with respect to temperature, it's just R over molar volume minus b.
这样我们求,压强对温度的偏导数,结果等于R除以摩尔体积V杠减去b的差。
p This is going to get us dH/dp constant temperature. What is this experiment?
这帮助我们理解恒温条件下的偏H偏,那么这个实验具体是什么呢?
These things have to be equal to each other.
这两个偏导数是相等的。
Because these mixed second derivatives are the same thing.
因为这两个混合二阶偏导数,是相等的。
v du/dV under constant temperature. du/dT v under constant volume. You use the Joule expansion to find these quantities.
像偏u偏v,恒温下的偏u偏,恒容下的偏u偏,你们知道怎么运用焦耳定律。
So d/dT of dA/dV, just like this.
即对dA/dV求对温度T的偏导数。
What is dH/dT as a function, keeping pressure constant, what is dH/dp, keeping temperature constant?
恒定时偏H偏T是什么,温度恒定时的偏H偏p又是什么呢?,好的,让我们解决第一个问题?
So we already know that. So now we can write CpdT or differential dH as Cp dT plus dH/dp, pdp constant temperature, dp.
我们已经知道了这个,所以我们现在,可以写出H的微分式:dH等于,加上恒温时的偏H偏。
We already did that. OK, dH/dT constant pressure is Cp. That was easy one.
我们已经做过这个计算了,好的,在恒压,状态下的偏H偏T就是Cp,这个很简单。
dT That means that dH is also equal to dH/dT, constant pressure dT. All right, so now I've T ot more dH/dT under constant pressure.
也等于偏H偏T恒压乘以,现在我已经得到了在恒压,状态下的偏H偏。
So, using those, now, what happens if we take the second derivative of A, the mixed derivative, partial with respect to T and the partial with respect to V.
如果我取A的二阶导数,混合导数,对T偏微分,再对V偏微分。
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。
du/dT And we discover that du/dT at constant V T is equal to du/dT at constant V.
可以发现恒定体积下的,等于恒定体积下的偏u偏。
OK, so now we have the other one, p dH/dp constant temperature.
好的,现在我们来研究另一个量,在恒温条件下的偏H偏。
dA/dT dS/dV So this is negative dS/dV.
是负S,It’s,negative,S。,这个二阶偏导数是负的恒定温度下的。
T Remember, we're trying to get delta H, p we're trying to get dH/dT constant pressure and dH/dp constant temperature. OK, these are the two things were trying to get here.
想要得到在恒压状态下的偏H偏,和在恒温状态下的偏H偏,好的,这是两个我们,在这里想要得到的东西。
That's where that term comes from, du/dV dV/dT.
乘以偏V偏T,p恒定,这项的来源。
The dA/dV is calculated at constant temperature.
就像这样,dA/dV是在恒定温度下的偏导数。
With respect to n, the number of moles.
对n的偏导数,这里的n是摩尔数。
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