acids and bases Flashcards
acid definition
proton donor
base defintion
proton acceptor
strong acid definition
an acid that fully dissociates
weak acid defintion
an acid that partially dissociates
pH=
-log10[H+]
[H+]=
10^-pH
ionic product of water (kw)=
[H+][OH-]
when calculating pH of strong acid use
pH=-log10[H+]
when calcualting pH of strong base use
rearrange kw=[H+][OH-] to get [H+] then use pH=-log10[H+]
when calcuating pH of a weak acid use
ka=[H+]^2/[HA] and rearrange to get [H+] and then use pH=
when calcuating pH of buffer use
ka=[H+][A-]/[HA] and rearrange to get [H+] and then use pH=
what does acid-base equillibria involve
transfer of protons
water is
slighty dissociated
what varies the value of Kw
temp
water dissociation equation endothermic
pKa=
-log10Ka
mirrors pH scale lower the pH lower the pKa value
in a monoprtic acid [H+] =
[HA]
relationship between [HA] and [H+] in diprotic acid
[HA] x2 = [H+]
in a triprotic acid [H+] =
[HA]/3
what does a buffer solution do
maintains an approximately constant pH despite dilution or addition of small amounts of acid or base
acidic buffer solutions contain
excess weak acid and the salt of that weak acid
basuc buffer solutions contain
excess weak base and the salt of that weak base
at half nuetralisation point ka=
[H+]
at half netralisation piont pKa=
pH
if acid is added to buffer solution
add to the acid
if base is added to alkali solution
take from the acid
