dT/dp is mu JT. So for a real gas like air, this is a positive number. It's not zero.
所以对于像空气这样的真实气体,这是一个正数,不等于零。
I know I only need 2, so I can relate dV dV to dp through the ideal gas law.
我只需要两个就够了,因此可以用,理想气体状态方程消去。
If T is less than T inversion, you have the opposite case, and dT/dp is greater than zero.
如果T比转变温度低,情况就相反,偏T偏p大于零。
V So this nR over V. And then, using the relation again, T we can just write this as p over T.
恒定温度下的dp/dT等于nR除以,再次利用状态方程,可以把它写成p除以。
So for an ideal gas then, dH/dp under 0 constant temperature, that has to be equal to zero.
所以对于理想气体,偏H偏p在恒温下,等于。
So then, just like we saw, analogous to what saw just before, dS/dp it's T dS/dp at constant T.
就像我们看到的,就像我们刚才看到的一样,结果是T乘以恒定温度下的。
dG/dp And this is dG/dp at constant temperature.
这是恒定温度下的。
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?
nRT So, dp/dT, for our ideal gas, at constant volume, remember pV is nRT.
对于理想气体状态方程pV等于,所以对理想气体。
In other words, the order of taking the derivatives with respect to pressure and temperature doesn't matter And what this will show is that dS/dp dS/dp at constant temperature, here we saw how entropy varies with volume, this is going to show us how it varies with pressure.
换句话说,对温度和压强的求导顺序无关紧要,结果会表明,恒定温度下的,对应我们上面看到的,熵如何随着体积变化,这个式子告诉我们,熵如何随着压强变化。
Normally I couldn't do that Vdp because this term would have p dV plus V dp, but we've specified the pressure is constant, so the dp part is zero.
一般情况下我不能这么写,因为这一项会包含pdV和,但是我们已经假定压强为常数,所以包含dp的部分等于零。
Vdp So dH is just du plus p dV plus V dp.
所以dH等于du加上pdV再加上。
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。
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?
d2G/dpdT So d squared G dT dp is equal to d squared G dp dT.
所以d2G/dTdp等于。
du/dV So now our du/dV, dp/dT at constant T is just T times dp/dT which is just p over T minus p, it's zero.
现在我们的恒定温度下的,等于T乘以dp/dT,在这里,等于p除以T,最后再减去p,结果是0。
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。
Vdp So dG is minus S dT plus V dp.
结果是dG等于负SdT加上。
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。
So if you had a high temperature, this a small compared to b. If you're negative which means that dT/dp at constant H is less than zero.
高于反转温度,这一项相比于b很小,意味着H恒定时,偏T偏p小于零。
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。
dT/dp is positive. dT/dp is positive.
偏T偏p是正数,好的这就是。
JT dT/dp is positive, well that's mu JT.
偏T偏p就是μ
OK, in a few weeks, you're going to find out that we can calculate dH/dp from this equation of state, and you're going to find p out that dH/dp from that equation of state b-a/RT is proportional to b minus a over RT.
好,在接下来几个星期里,你们将知道从这个状态方程,可以计算出偏H偏p,并且你们会发现,从这个状态方程得到的偏H偏,正比于。
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