Electrolysis

Question 1

if the carbon method for extracting metals doesnt work, what do we use?

Answer 1

So, for metals that are MORE reactive than carbon (above carbon on the reactivity series) we use electrolysis

Question 2

what is an ore how do we extract the metal normally

Answer 2

A metal ore is when a metal has reacted with other substances to form a rock (normally oxygen)

Question 3

how do we extract the metal normally

Answer 3

To extract the metal the metal from this ore, we use displacement reactions. We react carbon with the metal ore, so that it displaces the metal, leaving us with just the metal and carbon dioxide.

Question 4

what does electrolysis mean

Answer 4

Electro = electricity
Lysis = splitting
SO electrolysis = splitting something using electricity

Question 5

what is the solution in electrolysis called

Answer 5

electrolyte

Question 6

what is the pneumonic for the reactivity series

Answer 6

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Question 7

please stop calling me a careless zebrea instead try learn how copper saves gold

Answer 7

potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
(platinum)

Question 8

what type of compound can be used in electrolysis and why? (2)

Answer 8

Only ionic compounds can be used in electrolysis as they are the only ones that separate and can carry charge, and so can conduct electricity (when molten or aqueous), which is necessary in electrolysis

Question 9

how does electrolysis work, what do the electrodes do and the electrical circuit (3)

Answer 9

charged ions are attracted to the electrodes of opposite charges where they get discharged (so they gain or lose the necessary amount of electrons at the electrode which makes them atoms again)
The electric circuit keeps the flow of electrons going

Question 10

what is the order of discharge on each electrode

Answer 10

At the cathode, the least reactive substance gets discharged
At the anode the order of preference is halides, then hydroxide ions then anything else

Question 11

what is the difference between halides and halogens

Answer 11

Halides are group 7 IONS, halogens are group 7 ATOMS

Question 12

when writing formulae what is the big number infront of the compound and what is the little number within the compound

Answer 12

the big number at the front is how many lots of something there are. when you use the little number, it indicates that there is some bonding

Question 13

how to check half equations

Answer 13

To check half equations:

Make sure you have drawn an arrow and not equals
Check that it’s balanced
Make sure that the overall charge on each side is equal

Question 14

write the formula, which atom will be discharged at which electrode, and the half equations for
aqueous sodium chloride (3)

Answer 14

Formula: NaCl
Discharge:
Cathode ; H +1 ion
Anode ; Cl+1 ion
H2 —> e- + 2h+1
Cl2 + 2e- ——> 2Cl-1

Question 15

what are the uses of aluminium (6)

Answer 15

Uses of aluminium:

cooking foil
cars
pans
overhead power cables
drink cans
windows

Question 16

Why does aluminium extraction HAVE to be done using electrolytes:

Answer 16

Aluminium extraction can only be done using electrolysis because Aluminium is Above carbon so the carbon method cant be used for Aluminium extraction, thus electrolysis is used

Question 17

what is bauxite, its properties and how to obtain

Answer 17

Aluminium in its natural state is aluminium oxide which is found in an ore called bauxite
You get this ore by cast mining (digging it directly from the surface
Bauxite is mainly Al2O3 however it has impurities (iron oxide, so the waste solution is a rusty brown), so the first step in aluminium extraction is to extract the aluminium oxide from the impurities

Question 18

why do we have to use molten aluminium oxide in aluminium extraction

Answer 18

In aluminium extraction, you HAVE to use molten (l) aluminium oxide, not aqueous (aq), as with aqueous, hydrogen will be discharged at the cathode, but it’s aluminium which we want

Question 19

what do we do to keep the aluminium molten

Answer 19

We mix an ionic compound called cryolite with aluminium oxide to lower the melting point

Question 20

why do we need to replace the electrodes often in aluminium extraction

Answer 20

Oxygen reacts with hot carbon (graphite) electrodes to form CO2, and this means the electrodes need to be replaced quite often