chemical reactions paper 1 - copy
reaction of metals with oxygen?
metal + oxygen -> metal oxide
gaining oxygen?
oxidation
losing oxygen?
reduction reaction
metal reacting with water?
metal + water -> metal hydroxide + hydrogen
why do metals form positive ions?
because they lose electrons to get a full outer shell
what do acids produce in water?
hydrogen ions
what do bases produce in water?
hydroxide ions
how are bases and alkali different
bases are insoluble in water but alkali are soluble in water
what compound is a base usually
metal oxide or metal hydroxide
what is a neutralisation reaction + example
acid and alkali reacting to create a neutral solution
hydrogen ion + hydrooxide ion -> water
what does a metal + acid produce?
salt + hydrogen
what ending does a hydrochlorid scid salt have?
chloride
what name does a sulfuric acid salt end in?
sulfate
when reacting a metal with an acid what gets reduced and what gets oxidised
metal oxidised
acid reduced
what ending does a nitric acid salt have
nitrate
acid + metal carbonate?
salt + water + carbon dioxide
make a soluble salt? 5 steps
1. add a fixed amount of dilute sulfuric acid
2.add excess copper oxide and mix until its blue and powder is at the bottom
3.filter out powdered copper oxide with filter paper
4. add copper oxide to evaporating basin and heat until half the solution is left
5. leave for 24 hours to evaporate
what makes an acid strong?
fully ionises in water
what makes an acid weak?
partially ionises in water
what happens when the ph unit is decreased by one
hydrogen ions multiply by 10
titration practical? 7 steps
1. add 25cm(3) of sodium hydroxide into a conical flask with pipette
2.add 5 drops of indicator
3.place flask on white tile
4.fill a burette with sulfuric acid
5.add acid and start adding dropwise when colour starts to change
6.constantly swirl until solution is colourless
7.read volume in the burette from the bottom of the meniscus
what is the indicator used in titration
phenolphthalein