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CHEM 113- Unit 3
Question | Answer |
---|---|
percent dissociation | [HA]dissociated/[HA]initial x 100 |
% dissociation is higher | for more dilute initial acid concentrations |
polyprotic acid | >1 ionizable proton |
what Ka value (of a polyprotic acid) controls pH? | Ka1 |
anions of weak acids | are weak bases |
cations of weak bases | are weak acids |
small, highly charged metal cations | make H3O+ |
strong acids (6) | HCl, HBr, HI, HNO3, HClO4, H2SO4 |
lewis base | donates an electron pair |
lewis acid | accepts an electron pair |
what is formed in lewis acid/base rxns | adducts |
arrhenius acid | H+ |
arrhenius base | OH- |
bronsted-lowry acid | donates H+ |
bronsted-lowry base | accepts H+ |
buffers | contain a weak acid and its conjugate base (or vice versa) and are resistant to changes in pH |
ratio to be a buffer | 1:10 |
buffers have the highest capacity when | concentrations of acid and base are equal |
the more concentrated a buffer is... | the higher its capacity (more base/acid can be added and still work) |
useable range of a buffer | +-1 unit of the pKa |
buffer range | the pH range over which the buffer acts effectively |
indicators | weak acids with distinct color changes between protonated and deprotonated forms |
equivalence point | when moles of acid=moles of base |
equivalence point of strong acids/bases | always 7 |
when does pKa=pH | half way through buffer region [HA] and [A-] cancel |
pH of weak base/strong acid | <7 |
pH of weak acid/strong base | >7 |
polyprotic acids (in titrations) | have as many buffer region/equivalence points as ionizable protons |