Chemistry

Chemistry

Problem

A sealed container at a fixed temperature contains the equilibrium mixture for the reaction A ⇌ B. A particulate diagram shows 40 molecules of A and 60 molecules of B present at equilibrium. Calculate the numerical value of the equilibrium-constant, K, at this temperature.
Intuitive explanation

The equilibrium constant KK measures the ratio of products to reactants at equilibrium—it tells you how far the reaction has shifted. Since you have a snapshot of the system at equilibrium with a known number of each species, you can convert those molecule counts directly into concentrations (or use them as proportional values) and plug them into the equilibrium expression K=[B][A]K = \frac{[\text{B}]}{[\text{A}]}. The key insight is that at equilibrium, this ratio is fixed at a given temperature, regardless of the container size.

Intuitive explanation

The equilibrium constant KK measures the ratio of products to reactants at equilibrium—it tells you how far the reaction has shifted. Since you have a snapshot of the system at equilibrium with a known number of each species, you can convert those molecule counts directly into concentrations (or use them as proportional values) and plug them into the equilibrium expression K=[B][A]K = \frac{[\text{B}]}{[\text{A}]}. The key insight is that at equilibrium, this ratio is fixed at a given temperature, regardless of the container size.

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