Answer
For a gas the standard state is the pure gas at a pressure of exactly 1 atm; for a liquid or solid the standard state is the pure substance in its most stable form at a pressure of 1 atm and the temperature of interest (often taken to be 25 C ); for a substance in solution the standard state is a concentration of exactly 1 M. Standard enthalpy change is the change in enthalpy for a process when all reactants and products are in their standard
states.
Work Step by Step
Conceptual Question. No work needed.
