Acid Base Notes

This flashcard set covers key vocabulary and formulas related to acid-base chemistry, including pH, pOH, strong vs. weak acids/bases, Ka and Kb, and approximation methods for solving equilibrium problems. The notes emphasize when and why approximations are valid.

pH

A measure of the concentration of hydrogen ions in a solution; calculated as the negative logarithm of [H+].

pH Formula

pH = -log[H+]

pOH

A measure of the concentration of hydroxide ions in a solution; calculated as the negative logarithm of [OH-].

pOH Formula

pOH = -log[OH-]

pH and pOH Relationship

pH + pOH = 14

Strong Acid

An acid that completely dissociates into ions in solution.

Strong Base

A base that completely dissociates into ions in solution.

Weak Acid

An acid that only partially dissociates into ions in solution.

Ka

The equilibrium constant for the dissociation of a weak acid.

Kb

The equilibrium constant for the dissociation of a weak base.

Relationship Between Ka, Kb, and Kw

Kw = Ka * Kb

Approximation Method

Used to simplify calculations for weak acids and bases, assuming that the change in initial concentration is small.

Validity of Approximation Rule

If the initial concentration of the acid or base is 1000 times greater than Ka or Kb, the approximation is valid.

5% Rule

If the change in concentration is less than 5% of the initial concentration, the approximation is valid.