acids and bases Flashcards
what is a brønsted-lowry acid
a proton donor
what is a brønsted-lowry base
a proton acceptor
what is the definition of a strong acid
an acid that completely dissociates to ions when in solution with pH 0-1
what is a weak acid
an acid that only slightly dissociates when in solution with pH 3-5
what is pH
a measure of acidity and alkalinity
what is the ionic product of water equation and what is the value at 298K
Kw = [H+][OH-]
1 x 10^-14
what happens to pH of water as temperature increases and why
gets more acidic
forwards reaction is endothermic and hence favoured when temp of water is increased so more H+ produced
give the acid dissociation constant
Ka = [H+][A-] / [HA]
HA <———> H+ + A-
what is pKa and Ka
-log10 Ka = Ka
Ka = 10^ (-pka)
when should you use methyl orange indicator
reactions with a more acidic neutralisation point
it is orange in acids and turns yellow at neutralisation point
when should you use phenolphthalein indicator
for reaction with a more basic neutralisation point
pink in alkalis and goes colourless at the neutralisation point
how do you make a an acidic buffer and a basic buffer
add a weak acid and the salt of that weak acid to make an acidic buffer
add a weak base and the salt of that weak base
what is a buffer
a solution which is able to resist changes in pH when small volumes of acid or base are added
give colour of methyl orange in acid
red
give colour of methyl orange on basic side
yellow
at what pH does methyl orange colour change
3-5
litmus colour on acidic side
red
litmus colour on basic side
blue
pH when litmus colour changes
5-8
phenolphthalein colour on acidic side
colourless
at what pH does phenolphthalein change colour
8-10
colour of phenolphthalein on basic side
pink
