Electrochemical cells

Question 1

What are electrochemical cells

Answer 1

• consists of oxidation and reduction half-reactions connecteed via an external circuit
• allows electrons to move from the anode (where oxidation occurs) to the cathode (where reduction occurs)

Question 2

The two types of electrochemical cells

Answer 2

Galvanic:
- where chemical energy is converted into electrical energy

Electrolytic:
- where electrical energy is converted into chemical energy

Question 3

What is the function of a salt bridge in a galvanic cell?

Answer 3

• they allow for the reaction to continnue by preventing the build up of charge at either electrode
• if there wasn’t a salt bridge, there would be no flow of electrons

Question 4

What is a spontaneous redox reaction

Answer 4

• capable of occuring without the need of an external energy sources
• has value of E > 0
• galvanic cells

Question 5

What is a non-spontaneous redox reaction

Answer 5

• require an external energy source to occur
• has a value of E < 0
• electrolytic cells

Question 6

Explain the electrochemical series?

Answer 6

• the higher the half-equation on the electrochemical series –> the stronger the reducing agent
• meaning the more likely it is to be oxidised
• the lower the half-equation –> the stronger the oxidising agent
• meaning the more likely it is to be reduced

Question 7

Differences in galvanic and electrolytic?

Answer 7

Galvanic:
- requires no external energy source
- exist in seperate beakers with a connecting salt bridge
- anode is negative
- cathode is positive

Electrolytic
- requires an external energy source
- exists in a single beaker
- anode is positive
- cathode is negative