Question detail
For the equilibrium reaction 2D(g) ⇌ E(g) + F(g), if the equilibrium concentrations are [D] = 0.5 mol/dm³, [E] = 0.3 mol/dm³, and [F] = 0.2 mol/dm³, calculate the value of Kc.
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At a glance
Question
Type
exam_style
Style
Topic
Chemical equilibria, Le Chatelier's principle and Kc
Question
For the equilibrium reaction 2D(g) ⇌ E(g) + F(g), if the equilibrium concentrations are [D] = 0.5 mol/dm³, [E] = 0.3 mol/dm³, and [F] = 0.2 mol/dm³, calculate the value of Kc.
Answer
Kc = 0.3 / (0.5^2) = 1.2. This answer is anchored to Equilibrium constant Kc. This version is uniquely anchored to Equilibrium constant Kc. Retrieval anchor: A-level cue a0980f1a.
Explanation
Kc = 0.3 / (0.5^2) = 1.2. This answer is anchored to Equilibrium constant Kc. is correct because it supports the objective: Construct Kc expressions for homogeneous equilibria.. The reasoning stays within Equilibrium constant Kc and avoids drifting into a similar A-Level Chemistry idea. This item is treated as conceptual revision rather than a formal calculation item because the validated answer is an explanation or option choice, not a worked numerical response.
Common mistake
Incorrect Kc Expression Construction
Students often confuse the products and reactants when constructing Kc expressions, leading to incorrect formulas.
To construct the Kc expression, use the formula Kc = [products]^[coefficients] / [reactants]^[coefficients]. For example, for the reaction aA + bB ⇌ cC + dD, the correct expression is Kc = [C]^c [D]^d / [A]^a [B]^b. Substitute the equilibrium concentrations into the formula and calculate Kc.
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