## Chemistry: The Central Science (13th Edition)

$K_{c} = \frac{P[CO]^4}{P[Ni(CO)_{4}]}$ heterogeneous
The expression for Kc is the concentration of products raised to their respective stoichiometric coefficients divided by the concentration of the reactants raised to their stoichiometric coefficients. For the reaction Ni(CO)4 Ni + 4CO $K_{c} = \frac{[CO]^4}{[Ni(CO)_{4}]}$ Here the Ni is omitted because it is a solid ad you cannot have a concentration of a pure solid. Since the other reactants are gases, we do not measure their concentrations but rather the partial pressures $K_{c} = \frac{P[CO]^4}{P[Ni(CO)_{4}]}$ Since there are reactants in the gas phase and others in the solid phase, it is heterogeneous