Review of Ionization of Water, Acids, Bases, and Titration Curves

Flashcards reviewing key vocabulary and concepts related to the ionization of water, strong and weak acids and bases, titration curves, and buffer systems, including the Henderson-Hasselbalch equation.

Ionization of Water

The process where water molecules dissociate into hydrogen ions (H+) and hydroxide ions (OH-).

Keq

The equilibrium constant for the ionization of water, expressed as Keq = [H+][OH-] / [H2O].

Kw

The ion product of water, defined as Kw = [H+][OH-] = 10-14 M2 at 25°C.

pH

A measure of the hydrogen ion concentration in a solution; pH = -log10[H+].

pOH

A measure of the hydroxide ion concentration in a solution; pOH = -log10[OH-].

Neutrality

A condition where pH = pOH, indicating equal concentrations of H+ and OH-.

Acidic

A condition where the pH is below 7.

Basic

A condition where the pH is above 7.

Strong Acid

An acid that completely dissociates in solution.

Strong Base

A base that completely dissociates in solution.

Weak Acid

An acid that undergoes incomplete dissociation in solution; it is a proton donor.

Conjugate Base

The species formed when a weak acid loses a proton.

Weak Base

A base that undergoes incomplete dissociation in solution; it is a proton acceptor.

Conjugate Acid

The species formed when a weak base gains a proton.

Acid Dissociation Constant (Ka)

A quantitative measure of the strength of an acid in solution; Ka = [H+][A-] / [HA].

pKa

The negative logarithm of the acid dissociation constant (Ka); pKa = -log10Ka. Smaller pKa values indicate stronger acids.

Titration Curve

A plot showing the change in pH of a solution as a function of the amount of acid or base added during a titration.

Buffer

A mixture of a weak acid and its conjugate base that resists changes in pH upon addition of small amounts of acid or base.

Buffering Region

The region on a titration curve where pH changes are minimal with the addition of acid or base.

Henderson-Hasselbalch Equation

An equation relating the pH of a solution to the pKa of a weak acid and the ratio of the concentrations of the acid and its conjugate base: pH = pKa + log([A-]/[HA]).