Consider the decomposition of a metal oxide to its elements where M represents a
ID: 1051535 • Letter: C
Question
Consider the decomposition of a metal oxide to its elements where M represents a generic metal: M2O (s) -----------------------> 2 M (s) + 1/2 O2 (g) Delta Gf (kj/mol) for M2O, M and O = -8.00, 0, 0
What is the standard change in Gibbs energy for the reaction as written in the forward direction? Delta Grxn = ? kj/mol 2. What is the equilibrium constant for this reaction as written in the forward direction at 298 K? K = ? 3. What is the equilibrium pressure of O2 (g) over M (s) at 298 K? PO2 = ? atm
Explanation / Answer
delta G rx =delta G of products - delta G of reactants
delta G rxn = 0 - [ - 8 ]
delta G rxn = 8 KJ /mol
delta G = -RT ln Keq
Keq = 0.03959 at 298 Kelvin
Keq = pO2^1/2
pO2= 1.568*10^-3 atm