Key Terms
Bronsted-Lowry acid
Proton (H+) donor Bronsted-Lowry base: proton (H+) acceptor Acid-base reaction: transfer of a proton from donor to accep
Example
HF + H2O <-> H3O+ + F- HF is the acid; F- is its conjugate base. H2O is the base; H3O+ is its conjugate acid.
Amphiprotic
Can either donate or accept a proton depending on what it reacts with. Amphoteric: broader term; same idea but applies a
Water reacts with itself to a tiny extent
2 H2O <-> H3O+ + OH-
Strong acid or base
Essentially complete ionization in water; Ka or Kb is immeasurably large. Weak acid or base: partial ionization; Ka or K
Common strong acids
HCl, HBr, HI, HNO3, H2SO4 (first ionization), HClO4
Common strong bases
NaOH, KOH, Ca(OH)2, and other group 1 and 2 hydroxides
Standard method
Set up Initial, Change, Equilibrium concentrations; substitute into Ka or Kb expression; solve for x.
Simplifying assumption
If Ka << initial concentration, assume x is small compared to initial concentration. Check: x must be less than 5% of in
Monoprotic
One ionizable H (HCl, HCN, acetic acid) Diprotic: two ionizable H (H2SO4, H2CO3, H2S) Triprotic: three ionizable H (H3PO
Add strong base
It reacts with the weak acid component, consuming the base and producing more conjugate base. The weak acid ionization e
Add strong acid
It reacts with the conjugate base component, consuming the acid and producing more weak acid. The equilibrium shifts lef
Buffer capacity
The amount of strong acid or base a buffer can absorb before pH changes significantly (usually by 1 unit).
Principal buffer
Carbonic acid / bicarbonate system (H2CO3 / HCO3-)
Normal blood pH
7.35 to 7.45 [H2CO3] ≈ 0.0012 M; [HCO3-] ≈ 0.024 M