To ask questions like how much heat is released in a chemical reaction that takes place at constant temperature.
当我们想要知道,当一个化学反应在恒定的温度下发生时,会放出多少热量时。
OK, so this, what I've sketched here would be a constant pressure calorimeter. There's a reaction.
好,我画的就是一个恒压量热计,其中进行一个反应。
And our heat of reaction or enthalpy of reaction is defined as the enthalpy at constant pressure.
我们的反应热,或反映,的焓被定义为恒压,等温。
What is it when you run a chemical reaction under ordinary circumstances, what's constant?
如果你在通常的环境下进行化学实验,那么这些条件是什么?什么保持常数?
You're running some reaction. It's in the atmosphere. It's at constant pressure.
你已经在进行一些反应,在大气中,在恒温下。
Yes, and if we have gases involved, it's pretty similar, but now what will have is something like this. We'll have a reaction vessel that's sealed, it's constant volume.
如果涉及了气体,情况也很相似,只是现在的装置是这样的,我们有一个密封的反应容器,它的体积是恒定的。
Could be done, but easier is to just do the whole thing at constant volume, right, and just run the reaction that way and redo the calculation to be a constant volume rather than constant pressure calorimeter, right.
可以进行测量,但是如果在体积恒定的条件下,做这些会容易得多,还是这样进行反应,但是在等体而不是恒压条件下重新计算。
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