What does specific enthalpy mean?
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Ivl, where the capital I denotes specific enthalpy, and the lowercase v and l refer to steam and liquid (water) respectively (they are supposed to be subscripts, but they can’t be displayed). Now I would like to ask everyone: since I is specific enthalpy, what do the subscripts v and l beneath it mean? Specific enthalpy of steam-liquid mixture? I don’t understand it; please help me out! ! ! !
It refers to the enthalpy value per unit of substance, such as KJ/kg, KJ/mol, and so on
Note that the enthalpy value is a relative value, not an absolute one; absolute values cannot be measured.
It’s a relative value; that’s how it should be. The end product of the reactions involving most organic compounds is carbon dioxide and water. So, using carbon dioxide and water as the starting point for their enthalpy values is like using an altitude line. In other words, the specific enthalpy of a substance is the energy released when a unit amount of that substance is converted into carbon dioxide and water. Enthalpy should also take into account the state, such as temperature and pressure.