acid bases and salts
groups of chemicals
-acids -bases -metals -non-metals -covalent compounds -ionic compounds
acids
non-metals compounds in water can be concentrated or dilute
how do you test for acids
litmus test
how does litmus show acids
it turns red
bases
oxides and hydroxides of metals
alkalis
soluble bases they are hydroxides
what is the test for alkalis
calcium hydroxide + water = lime water (alkalis dissolved in water form an alkalis solution)
how does litmus show alkalis
litmus turns blue
what do all acids have in common
solutions of acids contain hydrogen ions
what do all alkalis have in common
all solutions of alkalis have hydroxide ions
what is the difference between weak and strong acids
weak acids are partially dissociated into ions in solutions -strong acids are completely dissociated into ions
which acids react to give which salts
hydrochloric acids - chlorides .sulfuric acids - sulfates . nitric acids - nitrates
typicall acid reactions
-with metals -acids+metals=salt +hydrogen -with bases-acids+bases=salt+water -with carbonates-acids+carbonates=salt+water+carbon dioxide
reactions of bases
with acids- salt+water -sodium, potassium, and calcium hydroxides react with ammonia gas
neutralisation
reaction with an acid giving salt and water
how to write ionic equations for neutralisation
write out equation showing ions -cross out ions that appear on both sides of this reaction -what is left is the ionic equation for the reaction
how does an insoluble base neutralise an acid
the base is a lattice when diluted by an acid the acid donate protons which breaks down the lattice
proton donors and acceptors
bases are acceptors and acids are donors
how do metals form oxides
metals react with oxygen to form basic oxides which belong to the larger group of compounds called bases
how are acid oxides formed
non-metals react with oxygen to form acidic oxides
amphoteric oxides
will react with acids and alkalis
examples of amphoteric oxides
aluminium oxides, zinc oxides
how to make salts starting with metals
1. add excess metal to acid bubbling will stop when acid is used up 2.metal is still left remove it by filtering leaving metal sulfate 3.heat solution to evaporate water and leave saturated solution
which metals does given method work for
magnesium , aluminium , zinc , iron
how to make salts starting with insoluble base / carbonate using copper oxide
1. add excess copper to dilute sulfuric acid until no more will dissolve 2. remove excess by filtering leaving copper sulfate in water 3. heat solution to obtain saturated solution crystals of copper sulfate will form
starting with an alkali
start with titration
what is titration
add one reactant to another with an indicator -the amount of reactants needed is now know -mix together without indicator
why is titration used to make salts using alkalis
both reactants are soluble so to avoid excess reactant getting into the product titration is needed
give examples of soluble salts
all nitrates, all chlorides , bromines and iodines
give examples of insoluble salts
chlorides, bromines and iodines of silver and lead -calcium barium and lead sulfate
precipitation
precipitation occurs when mixing reactants in solution gives an isoluble product the product is a precipitate
steps in making insoluble salt by precipitation with barium chloride and magnesium sulfate
1 make barium and magnesium solutions 2 mix them 3 when mised the barium and sulfate ions bond forming barium sulfate
how do you choose starting compounds to make insoluble salts
you need to mix a solution that contains positve and negative ions
what are hydrated salts
salts with water chemically bonded into their crystals
how to find concentration of an acid after titration
-calculate number of moles of alkali used -find equation , find molar ratio of acid to alkali - work out number of moles neutralised -calculate concentration of acid
equation to find concentration of acid
number of moles/ volume