AP Chemistry / Unit 7: Equilibrium
7.3 Reaction Quotient and Equilibrium Constant
Notes
For $aA+bB\rightleftharpoons cC+dD$:
$$K=\frac{[C]^c[D]^d}{[A]^a[B]^b}$$
- $Q$ uses the same expression with current values.
- Leave out pure solids and liquids.
Practice
$K$ expression for $N_2+3H_2\rightleftharpoons 2NH_3$:
Products over reactants, raised to coefficients.
For $CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$, $K=$
Solids are left out.
$Q$ differs from $K$ because $Q$:
$K$ is at equilibrium.
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