electrolysis

Question 1

What is an ion?

Answer 1

An atom that has gained or lost electrons to become stable.

positive = cation
negative = anion

Question 2

What is electrolysis?

Answer 2

Process where electrical energy decomposes electrolytes

Question 3

What are the components in electrolysis?

Answer 3

Electrode - rod of metal where current flows
Electrolyte - molten ionic compound
Anode - positive electrode
Anion - negative ion
Cathode - negative electrode
Cation - positive ion

Question 4

What is PANIC and OILRIG?

Answer 4

Positive is anode, negative is cathode

Oxidation is loss, reduction is gain

Question 5

Electrolysis in anode?

Answer 5

Oh- ions attracted. If halide ions are present then its discharged at anode, loses electrons & forms a halogen. If no halide ions are present OH- is discharged at anode, loses electrons & forms O2.

Question 6

Electrolysis in cathode?

Answer 6

H+ ions attracted. Either hydrogen or metal produced. If the metal is above hydrogen in reactivity series, hydrogen will be produced.

Question 8

What are electrode products?

Answer 8

Anode: brown fumes of bromine gas
Cathode: grey bead of molten lead

Question 9

What will the products of the electrodes always be?

Answer 9

Anode: non metal
Cathode: metal

Question 10

REDOX reactions at the electrodes?

Answer 10

Anode: ions are oxidised
Cathode: ions are reduced

Question 11

What is the method for electrolysis?

Answer 11

1. Use measuring cylinder to add 40 ml of copper sulfate into beaker
2. Measure & record masses of 2 pieces of copper foil, labelling one the anode, & one the cathode
3. Attach cathode to negative terminal of a dc supply, & anode to positive terminal
4. Turn on power supply, adjust to achieve constant current & observe what happens at each electrode
5. After 10 mins, turn off power &
   carefully remove electrodes & allow all liquid to evaporate - do not wipe the electrodes clean
6. Measure & record mass of electrode
7. Repeat experiment again with new electrodes & different currents