Predicting Equilibrium Shifts: Concentration, Pressure, Temperature, and Catalysts

All flashcards

What is dynamic equilibrium?

A state in which forward and reverse reactions continue at equal rates, so concentrations remain constant.

What does $Q<K$ indicate?

The net reaction proceeds forward, toward products, until the reaction quotient equals the equilibrium constant.

How does decreasing volume affect a gas equilibrium with unequal gaseous amounts?

It favors the side with fewer moles of gas.

How does heating affect an endothermic forward reaction?

It favors the forward direction, with heat treated as a reactant.

What does a catalyst change in an equilibrium system?

It speeds both reaction directions, helping the system reach equilibrium sooner without changing its composition.

Quiz questions

1. For a gas equilibrium with equal total gaseous stoichiometric coefficients on both sides, what is the effect of decreasing container volume at constant temperature?Answer: It does not shift the equilibrium by changing gaseous amounts.
2. For $\mathrm{N_2O_4(g) + heat \rightleftharpoons 2NO_2(g)}$, which direction is favored when the temperature is raised?Answer: The equilibrium shifts right, toward $\mathrm{NO_2}$.
3. For $\mathrm{N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)}$, why does high pressure favor ammonia formation?Answer: The product side has fewer moles of gas.
4. When a carbonated beverage is opened, the pressure of $\mathrm{CO_2}$ above the liquid falls. Which way does the dissolution equilibrium $\mathrm{CO_2(g)\rightleftharpoons CO_2(aq)}$ shift?Answer: It shifts left, allowing dissolved carbon dioxide to escape.
5. For a reaction at a given temperature, what does $Q>K$ indicate about the net reaction?Answer: It proceeds in reverse, toward reactants, until $Q$ equals $K$.