The relationship between the standard enthalpy of formation, as it is defined, and the assigned enthalpy is illustrated in Figure 1. (AHf°)T is the enthalpy of formation at some temperature T for which the reactant elements of the formation reaction have some arbitrary enthalpy value. enthalpy problems and answers.pdf ... The standard enthalpy of formation or standard heat of formation of a compound is the ... enthalpy problems and answers - Bing

And so, in the everyday world, if you have a bunch of methane sitting around, the fact that it has a negative heat of formation, or a standard heat of formation, because I have that naught here, or a negative standard change in enthalpy of formation-- those are all the same things-- tells me that methane is stable relative to its constituent ... Table A-1 lists selected entropy and enthalpy of formation values at 298 K for a number of atmospheric species. As much as possible, the values were taken from primary evaluations, that is, evaluations that develop a