AP Chemistry / Unit 7: Equilibrium
7.7 Calculating Equilibrium Concentrations
Notes
Use an ICE table (Initial, Change, Equilibrium), substitute into $K$, and solve. If $K$ is very small, assume $x$ is negligible compared with initial amounts.
Practice
$A\rightleftharpoons2B$, start with 1.0 M A. If $x$ M of A reacts, [B] at equilibrium:
Use the coefficient.
For $K=10^{-10}$, the "small $x$" assumption is:
Very little reacts.
$A\rightleftharpoons B$, $K=1$, start with 2.0 M A. At equilibrium, [B]=
$\displaystyle \frac{x}{2-x}=1$.
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