unit 8 must knows duel

what is a buffer

14 always!!

1.0 x 10^-14 at 25 C or 298 K

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

straight line up part of graph #miles of titrant = #moles of analyte concentration and volume of titrant is then used to determine concentration of analyte

HA(aq) + OH- --> A-(aq) + H2O(L) if weak acid is in excess --> a buffer --> Hendeson Hasselbalch equaiton if strong base is in excess, the moles of excess hydroxide ions is used for pH if acid and base are equimolar then the equilibrium concentr

how to increase/decrease buffering capacity

pH = 7 @ 25 C / 298 K

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)

in what range are buffers effective within 1 pH of its pKa, up or down

7, could be acid (pH) or base (pOH)

maximum buffering capacity pH = pKa

H2O pH is always... 7, could be acid (pH) or base (pOH)

equivalence point

strong acid strong base equivalence point

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

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)

pH + pOH = 14 always!!

in what range are buffers effective within 1 pH of its pKa, up or down

Kw = 1.0 x 10^-14 at 25 C or 298 K

strong acid-weak base reaction 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

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)

End this game?