C6

Question 1

what is electrolysis

Answer 1

the splitting up of a substance using electricity

Question 2

why does electrolysis need to be carried out as a molten or dissolved solution

Answer 2

as when it’s molten or dissolved the particles are allowed to move so electricity can flow

Question 3

what charge is the anode

Answer 3

positive

Question 4

what charge is the cathode

Answer 4

negative

Question 5

what an electrolyte

Answer 5

the substance being broken own by electrolysis

Question 6

which electrode do the negative charged ions go to

Answer 6

the anode (positive node)

Question 7

which electrode does the positively charged ion go to

Answer 7

the cathode (negatively charged node)

Question 8

what’s a positive ion called

Answer 8

cations

Question 9

what’s a negative ion called

Answer 9

anions

Question 10

what is oxidation

Answer 10

loss of electrons
gain of oxygen

Question 11

what is reduction

Answer 11

gain of electrons
loss of oxygen

Question 12

where does reduction happen

Answer 12

at the cathode

Question 13

where does oxidation happen

Answer 13

at the anode

Question 14

give the half equation for Mg 2+

Answer 14

Mg2+ + 2e- —-> Mg

Question 15

what is always produced if an aqueous solution is electrolysed

Answer 15

H+
OH-
the electrolysed electrolyte

Question 16

give the equation for water undergoing electrolysis

Answer 16

H20 = H+ + OH-

= the symbol for a reversible reaction

Question 17

what are the 2 rules for aqueous electrolysis

Answer 17

rule 1: the least reactive positive cation (positive ion) will be DISCHARGED at the cathode.

rule 2: if a halide is present as one of the negative anions (negative ion) then that would be DISCHARGED at the anode as a gas. If no halide is present then the OH- will be oxidised and would be DISCHARGED at the anode as 02 gas.

Question 18

what happens to the H+ and OH- ions at the end of the electrolysis

Answer 18

they react together to form water (pani [pronounce p-ah-knee])

Question 19

name the reactivity series in order with carbon and hydrogen

Answer 19

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

Question 20

name the formula for a nitrate ion

Answer 20

NO3 -

Question 21

name the equation for a hydroxide ion

Answer 21

OH 1-

Question 22

name the equation for a sulphate ion

Answer 22

SO4 2-

Question 23

name the formula for a hydrogen ion

Answer 23

H 1+

Question 24

name the equation for a carbonate ion

Answer 24

CO3 2-

Question 25

name the equation for an ammonium ion

Answer 25

NH4 1-

Question 26

what is a base

Answer 26

anything that can neutralise an acid

Question 27

what are the 2 types of bases

Answer 27

there are the insoluble ones: alkaline
and the non-insoluble ones

Question 28

what do all alkaline have in common

Answer 28

they all contain OH- ions

Question 29

what do alkalis do when they are dissolved

Answer 29

they undergo ionisation

Question 30

what do all acids have in common

Answer 30

they all have H+ ions in them

Question 31

what process does acids undergo when they are dissolved in water

Answer 31

ionisation

Question 32

name the steps in extracting aluminium

Answer 32

1. open cast mining - bauxite ore is dug up. rocks from that ore is removed leaving behind aluminium oxide
2. cryolite is added to the aluminium oxide to lower the melting point of aluminium oxide. it’s then melted down.
3. the outside wall of the electrolysis tank acts like a cathode so the aluminium forms at the walls and falls to the bottom of the tank.