Electrochemistry Flashcards

1
Q

what is an electrolyte

A

a substance that condducts electricity when dissolved in water or molten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Under what two circumstances in which ionic compounds can conduct electricity/ act as electrolytes

A

If dissolved in water/ solution
If molten

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how can an electric current be conducted through an electrolyte

A

ions are avlailable and free to move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is electrolysis

A

the passing of electricity through an electrolyte to cause a chemical reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is an electrode

A

a solid material that conducts electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what occours at the cathode

A

reduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what occours at the anode

A

oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

decribe the obervations seen ( using green copper (II) chromate solutions)

Demostrating the movement of ions when connected to a electrical current

A

Observation: a yellow colour will migrate towards the anode and a blue colour will migrate towards the cathode.
The yellow colour caused by the chromate ions.
The blue colour is caused by the copper (II) ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Inert electrodes reaction

A

electrodes do not react with the electroyte in which they are placed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Active electrodes reactions

A

electrodes that react with the electroyte in which they are placed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Inert electrodes suitable to use for these electrolysis

A

Platinum
Graphite (Carbon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Active electrodes suitable to use for these electrolysis

A

Copper electrodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

H2O will always reduce before the following ions

A

So4 2-
Na+
K+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what was the result/ Observation

Electrolysis of acidified water (H2o + H+) using inert electrodes

A
  • Bubbles of Hydrogen gas will collect over the cathode
  • Bubbles of oxygen gas will collect over the anode
    the volume of hydrogen will always be double the amount of oxygen formed ( 1 mole of hydrgen formed for every half mole oxygen formed)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Balanced chemical equation for reaction at cathode

Electrolysis of acidified water (H2o + H+) using inert electrodes

A

2H+ + 2e- → H2↑

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

balanced chemical equation for reaction at anode

Electrolysis of acidified water (H2o + H+) using inert electrodes

A

H2O - 2e- → 2H+ + 1/2O2↑

17
Q

Describe the reacrion/ result

Electrolysis of sodium sulfate (NaSO4) using inert electrodes

A
  • Bubbles of hydrogen gas will collect over the cathode.
  • The universal indicator turns from green to blue at the cathode.
  • Bubbles of oxygen gas collect over the anode.
    The universal indicator turns from green to red at the cathode
    the volume of hydrogen will always be double the amount of oxygen formed ( 1 mole of hydrgen formed for every half mole oxygen formed)
18
Q

Balaced chemical equation describing the reaction at the Cathode

Electrolysis of sodium sulfate (NaSO4) using inert electrodes

A

2H2O - 2e- → H2↑ + 2OH-

19
Q

Balaced chemical equation describing the reaction at the anode

Electrolysis of sodium sulfate (NaSO4) using inert electrodes

A

H2O - 2e- → 2H+ + 1/2O2↑

20
Q

list the reactions and obervations

Electrolysis of potassium iodide (KI) solution using inert electrodes

A

Bubbles of Hydrogen gas will collect over the cathode
Phenolphthalein turns from colourless to pink at the cathode
A red-brown colour will form at the anode due to the formation of iodine (I2)

21
Q

Write a balanced equation for the reaction that occours at the cathode

Electrolysis of potassium iodide (KI) solution using inert electrodes

A

2H2O - 2e- → H2↑ + 2OH-

22
Q

Write a balanced equation for the reaction that occours at the anode

Electrolysis of potassium iodide (KI) solution using inert electrodes

A

2I- - 2e- → I2

23
Q

Describe the result/ observation

Electrolysis of aqueous copper sulfate (CUSO4) using active electrodes

A
  • The pure copper cathode increases in mass as the Cu 2+ ions in solution are reduced to Cu
  • The impure copper anode is ‘eaten away’ and decreases in mass and the cu atoms in the anode are ocidised to CU 2+
    Impurities are undissolved and fall to the bottom of the beaker under the anode
24
Q

describe the reaction at the cathode

Electrolysis of aqueous copper sulfate (CUSO4) using active electrodes

A

Cu 2+ +2e- → Cu↓

25
Q

Describe the reaction at the anode

Electrolysis of aqueous copper sulfate (CUSO4) using active electrodes

A

Cu - 2e- → CU2+

26
Q

Give two applications of using electrolusis using active electrodes

A

Purification of copper
Electroplating

27
Q

give two examples of electroplating

A

cutlery electroplated with silver
Bath fittings plated in nickel and chrominum

28
Q

give two advantaged to electroplating one metal with another

A

the object appers more attractive
The object is more resistant to corrsion