pV=RT dT here because the pressure is constant, dV=RdT/p so dV is equal to R over p dT.
因为对1摩尔气体有,于是。
P dV is equal to R dT. pV = RT for 1 mole, pdV=RdT so I just take dV here.
对等压过程,那么。
dU=CvdT pV=RT So I can write du is Cv dT and pV is equal to RT.
于是。
pV=RT p plus a over v bar squared times v bar minus b equals r t. All right if you take a equal to zero, these are the two parameters, a and b. If you take those two equal to zero you have p v is equal to r t.
我们就回到,也就是理想气体,状态方程,下面我们来看看,这个方程。
And then V minus the excluded volume term is equal to RT. Two parameters, this is the attraction between two atoms or molecules in the gas phase.
以及V减去一个排斥项,等于RT,两个参数,这是气体状态下两个原子,或者分子之间的吸引力。
I'm going to call it r. It's going to be the gas constant, and now I have r times t is equal to the limit, p goes to zero of p r.
如果去掉p趋于0的条件,在有限压强下都,保持RT=pV的关系。
Minus p, right? But in fact, if you go back to the van der Waal's equation of state b here's RT over v minus b.
再减去p,对吗,但是实际上,如果你代回范德瓦尔斯气体的状态方程,这里是RT除以摩尔体积减去。
b It's RT over molar volume minus b minus a over molar volume V squared.
它等于RT除以摩尔体积V杠减去,再减去a除以摩尔体积的V杠平方。
RT So it's delta u plus RT, we can say T1 is the n temperature we've used here, delta n of the gas.
所以它应该是ΔU加,我们可以在这里用T1,气体的Δ
RT/V this expression becomes Cv dT over T is equal to CvdT/T=-RdV/V minus R dV over V.
这样,or,RT,over,V,bar。,So,now,这个等式就,可以化成。
Now if you're at the temperature which is b higher than the inversion temperature, in that case here, a over RT is small compared to b, and this is going to turn out to be negative.
T>Tinv】,这时a/bR小于,结果是负数,因此如果温度。
So it's RT over molar volume minus b.
等于RT除以摩尔体积减去b的差。
V RT over V.
因此等于RT除以。
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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