Question

When the oxide of generic metal M is heated at 25.0 °C, only a negligible amount of M is produced.
O2M(s) ----> M(s) +O2(g) delta G= 290.5 Kj/mol

When this reaction is coupled to the conversion of graphite to carbon dioxide, it becomes spontaneous. What is the chemical equation of this coupled process? Show that the reaction is in equilibrium, include physical states, and represent graphite as C(s).

I got the coupled reaction is:
O2M(S)+C(S)>>M(S)+CO2(G)

ive been trying for the thermodynamic equillibrium constant which is the next part of the question:

I got ln(0.04193) and did e^-3.17 but its wrong. can anyone help?

Answer 1

I've just moved and don't know where my tables are but here is what you do.
MO2 ==> M + O2 dG = 290.5 kJ/mol
C + O2 ==> CO2 dG = look in the tables for dGf.
Add equation 1 to equation 2 to obtain the equation you want which is
MO2 + C ==> M + CO2 and dGrxn = dGf for eqn 1 + dGf for eqn 2.
Then dGrxn = -8.314(298)*lnK

Answer 2

thankyouu so much