What three conditions define the standard reference state Wh

Solution

In mechanical standard reference state is the reference point from which various thermodynamic properties are defind. In General Internal Energy (u) = 0 , Entropy (s) = 0 and triple point of water is used as reference for defining various properties asuch as enthalpy etc.

The standard state of a substance does not have to exist in nature for example it is possible to calculate values for steam at 298.15 K and 10⁵ Pa, although steam does not exist (as a gas) under these conditions. The advantage of this practice is that tables of thermodynamic properties prepared in this way are self-consistent. and we can not attend zero entropy state pratically.