# Consider the decomposition of a metal oxide to its elements, where M represents a generic metal

Consider the decomposition of a metal oxide to its elements, where M represents a generic metal.

M203(s)—> 2M(s) + 3/2 O2(g)

info given for Gf(kJ/mol):
M203= -6.70
M(s)=0
O2(g)= 0

what is the standard change in Gibbs energy for rxn as written in forward direction? (kJ/mol)
What is the equilibrium constant (K) of this rxn, as written in forward direction at 298K?

What is the equilibrium pressure of O2(g) over M(s) at 298K? (atm)

Concepts and reason

• The difference between free energy of products and free energy of reactants is represented as standard free energy change of the reaction.
• The ratio of concentration of a product to the ratio of concentration of a reactant is represented as equilibrium constant. The equilibrium constant is expressed as.
• The equilibrium constant, in terms of partial pressure, is represented as equilibrium pressure.

Fundamentals
The standard Gibb’s free energy change can be calculated by: