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。

麻省理工公开课 - 热力学与动力学课程节选

And if I do that then I can find out the change in enthalpy of this reaction. It's just going to be the heat of formation of these three moles of water, minus the heat of formation of the iron oxide. OK.

我就能得到这个,反应的焓的变化,它就是三摩尔水,的生成热，减去氧化铁的,生成热，好。

麻省理工公开课 - 热力学与动力学课程节选