C3.4 - Electrolysis

Question 1

what is electrolysis the process of?

Answer 1

• breakdown of a liquid during the conduction of electricity
• process in which an electric current is passed through a compound, causing a chemical change

Question 2

what is required for electrolysis to happen?

Answer 2

current to flow

Question 3

what is the electrolyte?

Answer 3

ionic compounds that dissolve in water/ ionic compound in the liquid state making a solution that conducts electricity

Question 4

why are electrolytes able to conduct electricity?

Answer 4

the ions are able to move around (when an ionic compound is dissolved)

Question 5

where do positively charged ions move to when a voltage is applied?

Answer 5

cathode electrode

Question 6

where do negatively charged ions move to when a voltage is applied?

Answer 6

anode electrode

Question 7

what charge does the anode have?

Answer 7

A-NO (so opposite)

Positive

Question 8

what charge does the cathode have?

Answer 8

negative

(remember cat paws -> cations are positive therefore cathode is negative)

Question 9

what happens when an ion touches an electrode?

Answer 9

electrons are transferred (producing elements/whole atoms)

Question 10

what happens when voltage is applied across an electrolyte?

Answer 10

charged ions are attracted to the oppositely charged electrodes

Question 11

what is convection?

Answer 11

the process in which ions in the electrolyte move to replace discharged ions

Question 12

what do water molecules in solutions split up to form?

Answer 12

H+ ions (hydrogen)

OH- ions (hydroxide)

Question 13

what does the product formed at the cathode depend on?

Answer 13

reactivity of the metal

Question 14

what does the product formed at the anode depend on?

Answer 14

if halide ions are present

Question 15

if halide ions are present at the anode what happens?

Answer 15

the halogen is produced

Question 16

what happens if halide ions are absent at the anode?

Answer 16

oxygen is produced

Question 17

what happens if the metal ion is more reactive than hydrogen at the cathode?

Answer 17

hydrogen is produced

Question 18

what happens if the metal ion is less reactive than hydrogen at the cathode?

Answer 18

the respective metal is produced

Question 19

does oxidisation or reduction happen at the anode?

Answer 19

oxidisation (ions lose electrons)

Question 20

does oxidisation or reduction happen at the cathode?

Answer 20

reduction (ions gain electrons)

Question 21

what are inert electrodes?

Answer 21

electrodes that are not changed during electrolysis (copper/platinum/graphite)
USED AS ANODE/CATHODE

Question 22

what happens during the electrolysis of water?

Answer 22

hydrogen ions are discharged at cathode, hydroxide ions are discharged at anode

Question 23

what are the four metals less reactive than hydrogen?

Answer 23

copper, silver, gold, platinum

Question 24

what electrode is the object your want to coat in electrolysis?

Answer 24

cathode

Question 25

which electrode is the piece of the metal you want to coat the object with?

Answer 25

anode