AP Chemistry/Acids and Bases

Polyprotic Acids

Can donate more than one hydrogen ion. (Bronsted-Lowry)

Titration

Titration is the combining of a known concentration solution with an unknown concentration solution. The titration is stopped at the equivalence point, where all of the acid or base has been reacted. Polyprotic acids have more than one equivalence point. This is described by the equilibrium law of volumetric analysis: $MVn={\text{constant}}$ or simply $M_{1}V_{1}n_{1}=M_{2}V_{2}n_{2}$ , where $M$ is the mass, $V$is the volume of titrating acid drained from burette to the conical flask containing titrated base of volume a little more than that untitrated base in pippet, $n$ is the number of moles of that acid.

Conjugate Acids and Bases

Conjugates differ by one hydrogen ion. Strong acids have weak base conjugates, and vice versa.

Water Dissociation Constant

$K_{w}=[H^{+}][OH^{-}]=10^{-14}$ at 298K.

Henderson-Hasselbalch Equation

The Henderson-Hasselbalch Equation finds the pH of a buffer solution by finding the ratio of conjugate base to acid and adding it to the pKa of the acid.

$pH=pK_{a}+\log _{10}({\frac {[A^{-}]}{[HA]}})$

For the chemical reaction:

${\ce {HA -> H+ + A-}}$

AP Chemistry

The Basics · Periodicity · Solids and Liquids · Gasses · Reactions · Stoichometry · Thermodynamics · Solutions · Acids and Bases · Equilibrium · Electrochemistry · Nuclear Chemistry · Organic Chemistry

Appendix

Constants and Equations · About the AP Exam