Chemical Cells
Compare different types of chemical cells and understand their working principles
VOLTMETER
0.00 V
Zn
Cu
Electrolyte: Dilute H₂SO₄
Electrochemical Series
Half-equations are written as reductions; the more negative E°, the stronger the reducing agent.
Increasing oxidising power
| Half-equation | E°/V |
|---|---|
| Mg²⁺(aq) + 2e⁻ ⇌ Mg(s) | -2.37 |
| Zn²⁺(aq) + 2e⁻ ⇌ Zn(s) | -0.76 |
| Fe²⁺(aq) + 2e⁻ ⇌ Fe(s) | -0.44 |
| Pb²⁺(aq) + 2e⁻ ⇌ Pb(s) | -0.13 |
| Cu²⁺(aq) + 2e⁻ ⇌ Cu(s) | +0.34 |
| Ag⁺(aq) + e⁻ ⇌ Ag(s) | +0.80 |
Increasing reducing power
HKDSE Tip
- Electron flow:Electrons flow from the more reactive metal (-ve pole / anode) to the less reactive metal (+ve pole / cathode) through the external circuit.
- Voltage:The further apart the metals are in the ECS, the higher the voltage produced.
- Energy change:Chemical energy is converted to electrical energy.
Lab Guide
- 1Choose Electrodes
Select two different metals from the list as electrodes.
- 2Observe Voltage
Click "Start Cell" to observe the voltmeter reading and electron flow.
- 3Trends
Try different combinations to find which one produces the highest voltage.
Observation
Observe the animation first...
Half Equations
Half equations appear when the experiment ends.