My question(pdf file) is attached.
We usually define the activity of oxygen as a_0=P_(O_2)^(1/2)
A common reference state for oxygen gas is 1atm pressure at the temperature of interest.
Consequently,〖〖(a〗_0)〗_(P_(O_2 )=1) = P_(O_2)^(1/2)
When a metal is oxidized we can write M+1/2 O_2=MO, K=1/(a_M P_(O_2)^(1/2) )
At the metal oxide interface a_M=1 and K=1/〖(P_(O_2)^(1⁄2))〗_(M⁄MO)
Write an expression for the activity of oxygen where 〖(P_(O_2)^(1⁄2))〗_(M⁄MO) is taken as our reference state where a_0=1. Relate this activity to the activity of oxygen where the reference state is P_(O_2 )=1atm.
-My question(pdf file) is attached