GKFix MCQ Question

What is the equilibrium constant for the reaction CaCO3(s) ⇌ CaO(s) + CO2(g)?

• A. [CaCO3] / ([CaO][CO2])
• B. [CaO][CO2] / [CaCO3]
• C. [CO2]
• D. [CaO] / ([CaCO3][CO2])