weak acid-strong base reaction
H2O pH is always...
7, could be acid (pH) or base (pOH)
increasing/decreasing concentrations of buffer components, but keeping the ratios constant (if you don't it'll change the buffer capacity for either acid or base respectively)
Kw =
1.0 x 10^-14 at 25 C or 298 K
pH + pOH =
14 always!!
what is a buffer
solution that is resistant to a small pH change, it has to contain a weak acid or base pared with its conjugate salt(Na+, H3O-, etc...) and it creates neutral compounds, keeping pH relatively stable
if weak base is in excess --> a buffer --> Hendeson Hasselbalch equaiton
if strong acid is in excess, the moles of excess acid are used to determine pH
if acid and base are equimolar then the equilibrium concentrations are used to determine pH
pH = 7 @ 25 C / 298 K
maximum buffering capacity
pH = pKa
in what range are buffers effective
within 1 pH of its pKa, up or down
equivalence point
how do you calculate a buffer's pH
pH = pKa + log [A-]/[HA] ---> acids
pOH = pKb + log [BH+]/[B] ---> bases
the conjugate salt is on top, and the bottom is either the base or the acid
assume there is a limiting and excess reagent (because it will contain either a strong acid or base)
