Save
AQA GCSE Combined Science: Chemistry
Chemical Changes
Save
Share
Learn
Content
Leaderboard
Share
Learn
Created by
Michelle Egbe
Visit profile
Cards (26)
Electrolysis
Splitting up with
electricity
View source
Electrolysis process
1. Place
electrolyte
in
beaker
2. Use
electrodes
(
anode
and
cathode
)
3. Connect electrodes with
wire
4. Add power supply (e.g.
battery
)
5. Electric
current
passes through
electrolyte
View source
Electrolyte
Liquid or
solution
containing an
ionic
compound with
free-moving
ions
View source
Electrolytes
Aqueous
copper
sulfate
Molten
lead
bromide
View source
Electrodes
Solid
conductors,
generally made of
metal
or carbon
Anode (
positive
electrode)
Cathode (
negative
electrode)
View source
Negative bromide ions
Attracted to
positive
anode,
discharged to form
bromine gas
View source
Positive lead ions
Attracted to
negative
cathode,
discharged to form pure
lead
View source
Oxidation and reduction at electrodes
1. At anode: Bromide ions
oxidized
, lose
1
electron (
half
equation)
2. At cathode: Lead ions
reduced,
gain
2
electrons
View source
Overall, electrons transferred from
negative
ions to
positive
ions using
electricity
to convert ions to
pure
elemental forms
View source
Extracting reactive metals from their oxides
1.
Melt
the oxides into their molten
ionic
compounds
2. Reduce the metal in the oxide to remove the
oxygen
View source
Metals less reactive than carbon
Can be reduced with
carbon
View source
Metals more reactive than carbon
Require
electrolysis
to extract
View source
Electrolysis
Separates
ionic
compounds into their pure elements by passing an electric
current
through an
electrolyte
Requires the
ions
to be able to move
freely
View source
Extracting aluminium from bauxite
1.
Purify
aluminium oxide from
bauxite
2.
Mix
aluminium oxide with
cryolite
to
lower
melting point
3.
Melt
the mixture
View source
Electrolysis of molten aluminium oxide
1. Use a
beaker
to hold the molten
electrolyte
2. Use a positive carbon
anode
and negative carbon
cathode
3. Connect the electrodes with a
wire
and
power
source
View source
Reactions at the electrodes
1. At the
anode,
oxygen 2- ions form oxygen
gas
and
release
electrons
2. At the
cathode
, aluminium 3+ ions
gain
3 electrons to form molten
aluminium
metal
View source
Oxidation
Loss
of
electrons
View source
Reduction
Gain
of
electrons
View source
Reactivity series of
metals
Order of how easily metals form
positive
ions
View source
Metals
Have
electrons
in the
outermost
shell that they want to get rid of
Form
positive
ions when they react
View source
Metals included in reactivity series
Group
1
metals
Group
2
metals
Transition
metals
Carbon
Hydrogen
View source
Determining reactivity series
1. React each metal with
acid
or
water
2. Compare
reaction speed
and
violence
3. Measure
temperature change
View source
Fair test for comparing
reactivity
Use
same mass
and surface area of
metal samples
Use
same type and concentration of acid
View source
Reaction of metals with water
1. Form metal
hydroxides
and
hydrogen
2. Only most
reactive
metals react with water
View source
More
reactive
metal
Can
displace
less
reactive
metal in a solution
View source
Magnesium can displace iron in iron sulfate solution, but copper cannot displace
iron
in iron
sulfate
solution
View source