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what is an acid?
a substance that releases positive hydrogen (H+) when dissolved in water
what colour is litmus solution? (in acids, neutral, alkalis)
red in acids, purple in water, blue in alkalis
what colour is phenolphthalein?
colourless in acids and neutral solutions, hot pink in alkalis.
what colour is methyl orange?
red in acids, orange when neutral, yellow in alkalis
what does a concentrated/dilute acid mean?
concentrated and dilute refers to the amount of acid molecules dissolved in water. a concentrated acid will have a large amount of acid molecules dissolved in a certain amount of water.
what does a strong/weak acid mean?
strong and weak refer to how many of the acid molecules have been split apart into ions (dissociation/ionisation). a strong acid will completely dissociate into ions in water (so all of the acid molecules have broken apart and formed hydrogen ions) e.g. HCl is a strong acid and ethanoic acid is a weak acid.
what is a base?
bases are substances that can neutralise acids (normally metal oxides/hydroxides)
what is an alkali
alkalis are bases which are soluble in water. they release OH- ions when dissolved in water (generally soluble hydroxides). like acids, alkalis can also be strong/weak/concentrated/dilute.
(reactive) metal + acid —>
salt + hydrogen
bases/alkali + acid —>
salt + water
metal carbonate + acid —>
salt + carbon dioxide + water
ammonia + acid —>
ammonium salt
when is precipitation used?
when the base is soluble but the salt is insoluble
which solutions are used for precipitation?
___ nitrate and sodium ___
when is the excess base method used?
when the base is insoluble and the salt is soluble
which solutions are used for the excess base method?
___ oxide and acid
when is titration used?
when both the salt and base are soluble (sodium, potassium, ammonium salts)
which solutions are used for titration?
the appropriate acid and the appropriate hydroxide or carbonate
which salts are soluble?
all sodium, potassium, ammonium salts
all nitrates
common halides except silver and lead
common sulphates except lead, barium and calcium
which salts are insoluble?
silver and lead halides
lead, barium and calcium sulphates
common carbonates and hydroxides except sodium, potassium and ammonium
you should also be able to:
describe how to carry out an acid-alkali titration
describe the method used to prepare a pure dry sample of an insoluble salt
check the booklet for detailed answers.
Note 
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