Module 5: Redox & Electrode Potentials IPS (5.2.3)

Question 1

Measuring Electrode Potential

Answer 1

1. Prepare 2 standard half cells
   a. Concentration 1 mol dm⁻³ with inert Pt electrode, 298k
2. Connect half cells to voltmeter using wires
3. Prepare salt bridge by soaking strip of filter in saturated aq solution of KNO₃
4. Connect 2 solutions using bridge
5. Record standard cell potential from voltmeter

Question 2

Primary Cells

Answer 2

1. Non rechargeable and designed to be used once.
2. Electrical energy produced by reduction and oxidation at electrodes and cannot be reversed.
3. Zn and MnO₂ with KOH electrolyte

Question 3

Secondary Cells

Answer 3

1. Rechargeable and reactions can be reversed.

2. Lithium ions for modern appliances.

Question 4

Fuel Cells

Answer 4

1. Uses energy from reaction of a fuel with O₂ to create voltage
2. Fuel and O₂ flow into fuel cell and products flow out.
3. Can operate continuously as long as fuel and O₂ supplied.
4. Do not have to be recharged.
5. Hydrogen cell can have either acid or alkali electrolyte, with voltages staying at 1.23V.