AP Chemistry Unit 9 - Chemical Equilibrium

These flashcards cover key concepts related to chemical equilibrium, including definitions, constants, and principles relevant to the topic.

What is chemical equilibrium?

The state when the forward reaction rate equals the reverse reaction rate and net concentrations of reactants and products do not change.

What is dynamic equilibrium?

A state in which both the forward and reverse reactions occur continuously, leading to constant concentrations of reactants and products.

What is the equilibrium constant expression for the reaction N2O4(g) ↔ 2NO2(g)?

Kc = [NO2]^2 / [N2O4]

What happens to Kc if the reaction is product-favored?

Kc >> 1, indicating products predominance at equilibrium.

What is the law of mass action?

At equilibrium, the ratio of the concentrations of products to reactants raised to their respective coefficients is constant.

What does it mean if Kc << 1?

The reaction is reactant-favored; reactants predominate at equilibrium.

How can equilibrium be reached in a reaction?

Equilibrium can be reached regardless of whether we start with reactants or products.

What happens to the position of equilibrium if a reactant is added?

The system will shift to the right, favoring the formation of products.

What effect does an increase in temperature have on the equilibrium of an endothermic reaction?

It favors the endothermic direction, increasing Kc.

How are Kp and Kc related?

Kp = Kc(RT)^Δn, where Δn is the change in moles of gas.

What is the Ksp expression for the dissolution of AgCl?

Ksp = [Ag+][Cl-].

What is Le Chatelier's principle?

If a system at equilibrium is subjected to stress, the equilibrium will shift in a direction that partially alleviates that stress.

How is the solubility of a salt affected by the presence of a common ion?

The solubility is inhibited in the presence of a common ion.

What is amphoterism?

The ability of a substance to act as either an acid or a base.

What is a complex ion?

A metal ion bonded to neutral molecules or anions, typically formed through coordinate covalent bonds.