Before revision: For example, for nitrogen: N2 (molecular gas) 2 N (dissolved atoms) For the above reaction, the equilibrium constant, K, is: Where: c_{at is the concentration of the dissolved atoms into the metal (in the case above atomic nitrogen N) p_{mol is the partial pressure of the gas at the interface with the metal (in the case above, the molecular nitrogen N2) Therefore
After revision: For example, for nitrogen: N2 (molecular gas) 2 N (dissolved atoms) For the above reaction, the equilibrium constant, K, is: Where: cat is the concentration of the dissolved atoms into the metal (in the case above atomic nitrogen N) pmol is the partial pressure of the gas at the interface with the metal (in the case above, the molecular nitrogen N2) Therefore