electrolysis 5.5

Question 1

what is electrolysis

Answer 1

breaking down of a compound using electricity

Question 2

how does electrolysis occur

Answer 2

the substance to be broken down is connected into a circuit with a cell or battery

Question 3

what is the positive electrode called

Answer 3

anode

Question 4

what is the negative electrode called

Answer 4

cathode

Question 5

characteristics of electrodes

Answer 5

solid that conducts electricity but is inert

Question 6

what metals are usually used as electrodes

Answer 6

graphite (cheap)
platinum (expensive)

Question 7

what is the electrolyte

Answer 7

the substance to be broken down

Question 8

what are the only compounds that can be electrolytes

Answer 8

ionic compounds that are molten or dissolved as the ions are free to move

Question 9

what are the positive ions called

Answer 9

cations as they are attracted to the cathode

Question 10

what are the negative ions called

Answer 10

anions as the are attracted to the anode

Question 11

what does the electrolysis of magnesium chloride form

Answer 11

magnesium and chlorine

Question 12

what is seen at the anode in the electrolysis of magnesium chloride

Answer 12

bubbles of pale green gas

Question 13

what attracts to the anode

Answer 13

non-metal ions that form molecules

Question 14

what attracts to the cathode

Answer 14

metal ions form electrons

Question 15

what is seen at the cathode in the electrolysis of magnesium chloride

Answer 15

grey solid would form on the surface

Question 16

what does electrolysis of molten ionic compounds produce

Answer 16

its elements

Question 17

what happens to water molecules during the electrolysis of aqueous compounds

Answer 17

water molecules disassociate to form H+ and OH- ions

Question 18

how to pick which ion reacts at the anode

Answer 18

if a hailed ion (Cl-/Br-/I-) is present then the element is produced as normal
otherwise, O2 and H2O are produced

Question 19

how to pick which ion reacts at the cathode

Answer 19

if the metal is less reactive than hydrogen then the element is produced as normal
otherwise, H2 is produced

Question 20

what happens to the ions that don’t react

Answer 20

they remain leftover in the solution as a third product