Learning objective

Calculate Kc from equilibrium concentrations.

Read the explanation, check the common trap, then practise with flashcards and questions.

Start flashcards Try practice questions Topic hub

At a glance

Flashcards

Questions

Topic

Chemical equilibria, Le Chatelier's principle and Kc

Subtopic

Equilibrium constant Kc

AQA A Level ChemistryPhysical chemistry

Study support

Understand this objective

Short explanation

Calculate Kc from equilibrium concentrations. sits within Equilibrium constant Kc for Chemical equilibria, Le Chatelier's principle and Kc in AQA A-Level Chemistry 7405. A strong exam response should identify the relevant chemical relationship, choose the correct formula or representation where needed, substitute values or evidence carefully, and state the final conclusion with appropriate units or terminology. When revising this objective, focus on the distinction between the concept being tested and neighbouring ideas so that calculation steps, organic representations, or equilibrium reasoning do not collapse into a generic answer.

Key concepts

equilibrium constant (Kc)equilibrium concentrations

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.

Common mistakes

1 linked

Incorrect Kc Calculation: To fix this, remember that the Kc expression is constructed using the concentrations of products raised to the power of their coefficients, divided by the concentrations of reactants raised to their coefficients. For example, for the reaction aA + bB ⇌ cC + dD, the Kc expression is Kc = [C]^c [D]^d / [A]^a [B]^b. Substitute the equilibrium concentrations into this formula, perform the calculations, and ensure you express the final answer with the correct units (mol/dm³).

Revision tools