AP Chemistrymediummcq1 pt
At equilibrium a vessel holds [H₂] = 0.040 M, [Br₂] = 0.20 M, and [HBr] = 0.80 M for H₂(g) + Br₂(g) ⇌ 2HBr(g). What is Kc?
A.160
B.0.013
C.80
D.100
Explanation
Core Concept
The expression places products over reactants with coefficients as exponents: Kc = [HBr]² ÷ ([H₂][Br₂]). Substituting the measured values gives (0.80)² ÷ (0.040 × 0.20). The numerator evaluates to 0.64 and the denominator to 0.0080, so Kc = 80. Squaring [HBr] is required because its stoichiometric coefficient is 2.
Correct Answer
C80
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