That means that this temperature right here is the absolute lowest temperature you can go to that physically makes any sense.
是物理上不可能的状态,也就是说这一点,对应的温度是物理上。
And the path that I'm describing then, let's assume that we're raising the temperature up is this path right here.
经过一个,等压过程,路径就是这样。
But we've defined the enthalpy of those elements in their stable state at room temperature and pressure as zero, right?
但我们已经定义了这些,元素处于它们室温和常压下,最稳定的状态时的焓为零,对吧?
RT2 So it's R T2, right, now we're at a lower temperature times log the log of V4 over V3.
等于,这时温度比刚才低,乘以。
But if you touch the valve going into your tire which basically measures the temperature of the air going into your tire, that is getting hot, right.
以至于浑身发热,如果你摸气筒的阀门,相当于近似测量了进入轮胎的气体的温度,它会很热,对吧。
If there's no heat flow between the b and c, then I can say all right, a and c were the same temperature.
如果在与之间没有热量流动,那么我就可以说,好吧与处于相同的温度。
All right, so now we have the makings of a good thermometer and a good temperature scale.
这一常数只决定于温度,于是我们现在,可以定义一个理想的温度计和温标了。
PROFESSOR: Change the temperature, right.
改变温度。
It's tabulated in books, and this we can measure p in the experiment. Delta p here is the change in pressure from the left side to the right side, and we can put a thermometer, measure the temperature before the experiment and measure the temperature after the experiment.
这列在书上,这个量我们在,实验中也可以测量,在这里Δ,是从左边到右边的压强变化,我们可以放一个温度计,去测量实验前的温度,再去测量试验后的温度。
It's just how much heat is involved when we change the temperature. Now, the products have some heat capacity associated with them right, it takes a certain amount of heat if we make their temperature change, to either put it in or take it away, depending on which direction the temperature is changing.
问题就是当我们改变温度时,有多少热量发生了转移,生成物具有一定的热容,如果我们改变,它们的温度,就要输入或,提取一定的热量,这取决于温度改变的方向。
What we're really going to do in practice is we're going to measure, we're going to use our thermometer and say great, how much did the temperature change, right.
H1是零,实际上我们要做的,是用我们的温度计,测量温度改变了多少。
And that generally is just given by the heat capacity the calorimeter times delta T, right.. Because the heat capacity of the calorimeter just like this thing is not strongly temperature dependent, OK.
一般它就由量热计的热容,乘以ΔT给出,因为,量热计的热容,就像这张桌子一样,并不强烈依赖于温度。
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