Learning objective
Calculate Kc from equilibrium concentrations.
Read the explanation, check the common trap, then practise with flashcards and questions.
At a glance
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Flashcards
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Questions
Topic
Chemical equilibria, Le Chatelier's principle and Kc
Subtopic
Equilibrium constant Kc
Study support
Understand this objective
Quick explanation
Calculate Kc from equilibrium concentrations
- This point belongs to Chemical equilibria, Le Chatelier's principle and Kc, especially Equilibrium constant Kc.
- You need to be able to calculate Kc from equilibrium concentrations.
- The key ideas to know are concentration and Kc.
- Use the linked flashcards and practice questions to check recall, then practise applying the idea in an exam-style answer.
Key concepts
Why it matters
This objective helps connect Equilibrium constant Kc to exam-style questions, flashcards, and revision notes for Chemical equilibria, Le Chatelier's principle and Kc.
Quick student answer
For the equilibrium reaction N2(g) + 3H2(g) ⇌ 2NH3(g), if the equilibrium concentrations are [N2] = 0.5 mol/dm³, [H2] = 1.5 mol/dm³, and [NH3] = 2.0 mol/dm³, what is the value of Kc?
Direct answer
Kc = [NH3]^2 / ([N2][H2]^3) = (2.0)^2 / (0.5)(1.5)^3 = 4.00
Key terms
- Equilibrium: A state in a reversible reaction where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products.
- Dynamic equilibrium: A condition in which the concentrations of reactants and products remain constant over time, although both the forward and reverse reactions continue to occur.
Common trap
Incorrectly applying Kc expression: Always ensure that each concentration in the Kc expression is raised to the power of its respective coefficient from the balanced equation.
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Revision notestopic notes
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Open revision notesRelated learning objectives
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