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。
- And now temperature in Fahrenheit -- 212 all right, let's go ahead and pick an easy one like 212, Enter, and indeed equals 100 in Celsius.
现在输入华氏温度-,好的,让我们选一个简单的,像,回车,确实等于100摄氏度。
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。
Hydrogen gas it's in its most stable state, right at room temperature and pressure.
和常压下氢气是氢元素,最稳定的状态,这个小“0“
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。
HBr They form HBr which is a gas at room temperature and one bar, right.
和常压下是液体,它们生成了,在室温和1巴下是气体。
And I didn't specify the conditions, but if we were to do this under ordinary chemical conditions of some, you'd say room temperature and pressure, right, they all happen spontaneously.
我并没有特别说明反应条件,但是如果我们在通常的化学条件下,实现这些化学反应,比如在室温和大气压下下,他们都是自发的。
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。
OK, two, now it's a temperature change, right?
好,第二步,现在温度发生了变化,对吧?
Now to make that happen, it's not adiabatic, right. If I wanted to do that, I'd need a heating element or something to cool, so I could make that temperature change happen, right.
要实现这点,它就不会是绝热的,对吧,如果我想做到这点,我需要一个加热元件或什么制冷的东西,这样我才能让温度变化。
There is a change in temperature, right?
温度会改变,对吧?
Iron as an element is a solid. That's it's most stable state at room temperature and pressure, right, and so on. And then we can figure out heats of formation.
铁单质是固态,这是他在室温和常压下,最稳定的状态,然后我们,可以算出生成热,现在这个。
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。
Pressure and temperature, right.
老师:压强和温度对。
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。
du/dT constant pressure is the direct derivative with respect to temperature here, which is sitting by itself under constant volume keeping this constant but there is temperature sitting right here too.
偏U偏T,p恒定是对,温度的直接微分,而它本身对体积不变,保持它不变,但是这里也有一个温度,这就是偏U偏V,T恒定。
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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