Chemistry: Equilibrium

What is the relationship between hydronium and hydroxide ions in the pH scale?

The pH scale is logarithmic; pH = -log[H+] and pOH = -log[OH-].

How do you calculate [H+] from pH?

[H+] = 10^(-pH)

What is the pH of a solution with a high concentration of H+?

pH < 7 (Acidic)

What color does blue litmus paper turn in an acidic solution?

Red

What defines a Brønsted-Lowry acid?

A proton (H+) donor.

What defines a Brønsted-Lowry base?

A proton (H+) acceptor.

What happens to an acid after it donates a proton?

It becomes a conjugate base.

What is the difference between strong and weak acids/bases?

Strong acids/bases completely dissociate in solution; weak acids/bases only partially dissociate.

What is the relationship between pH and the strength of an acid?

A strong acid has a lower pH than a weak acid at the same molarity.

What is dynamic equilibrium?

A state where the forward and reverse reactions occur at the same rate, resulting in no net change in concentrations.

What does K_eq represent in a reaction?

The equilibrium constant, indicating the ratio of products to reactants at equilibrium.

What does it mean if K > 1?

The reaction is product-favored.

What is Le Chatelier's Principle?

When a system at equilibrium is stressed, it shifts to offset that stress.

How does increasing pressure affect a reaction at equilibrium?

It shifts the equilibrium toward the side with fewer moles of gas.

What happens to the equilibrium of an exothermic reaction when cooled?

The equilibrium shifts to the right (toward products).

What does the reaction quotient (Q) indicate?

The current status of a reaction; compares the ratio of products to reactants.

What does it mean if Q < K?

The reaction shifts right (toward products) because the ratio of products to reactants is too low.

What is the purpose of ICE charts?

To solve for unknown concentrations in weak acid/base systems.

In an ICE chart, how do you represent changes in concentration?

Use -x for reactants and +x for products.

What is the equilibrium expression for a reaction?

It is derived from the concentrations of products and reactants at equilibrium.

What does it mean if Q = K?

The system is at equilibrium.