AP Chemistryeasymcq1 pt
Which of these equilibria is classified as heterogeneous?
A.2NO₂(g) ⇌ N₂O₄(g)
B.CH₃COOH(aq) ⇌ H⁺(aq) + CH₃COO⁻(aq)
C.CaCO₃(s) ⇌ CaO(s) + CO₂(g)
D.H₂(g) + I₂(g) ⇌ 2HI(g)
Explanation
Core Concept
A heterogeneous equilibrium spans more than one phase. The calcium carbonate system contains two solids plus one gas, so three phases coexist while the equilibrium holds. Pure solids drop out of the constant, leaving K dependent on carbon dioxide alone. Every other listed system keeps all species in a single phase and is homogeneous.
Correct Answer
CCaCO₃(s) ⇌ CaO(s) + CO₂(g)
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