For the decomposition equilibrium CaCO3(s)⇌CaO(s)+CO2(g), which statement about the equilibrium-constant expression Kc is correct?
a) Kc=[CO2]1 because the gas appears in the denominator when it is a product; the solids are omitted.
b) [CaO] and [CO2] both appear in the expression, but [CaCO3] is omitted.
c) Only [CO2] appears in the expression because the concentrations of solids are omitted.
d) No species appear because the reaction contains solids; therefore Kc=1.