Galvanic Cells
Spontaneous redox reactions make electricity.
About this topic
A galvanic (voltaic) cell converts chemical energy into electrical energy using a spontaneous redox reaction. It has two half-cells joined by a wire and a salt bridge. Oxidation occurs at the anode (negative electrode) and reduction at the cathode (positive electrode); electrons flow from anode to cathode through the wire, and ions move through the salt bridge to keep charges balanced.
In the classic Daniell cell, a zinc electrode sits in zinc sulfate and a copper electrode in copper sulfate. Zinc is oxidised (Zn gives Zn2+ + 2e-) and copper ions are reduced (Cu2+ + 2e- gives Cu). The cell voltage is E cell = E cathode − E anode using standard reduction potentials: 0.34 minus (minus 0.76) = 1.10 V. A positive value means a spontaneous reaction. Without the salt bridge, charge would build up and the current would stop.
Batteries are galvanic cells: alkaline cells use zinc and manganese dioxide, lithium-ion cells move lithium ions between electrodes, and fuel cells combine hydrogen and oxygen to produce electricity and water. Rechargeable batteries run the reaction in reverse by applying an external voltage.
A misconception is that electrons flow through the salt bridge; only ions do. A memory aid is that an ox and a red cat: oxidation at the anode, reduction at the cathode.
Key ideas
- Anode oxidises, cathode reduces
- Salt bridge keeps balance
- Batteries are galvanic cells
Quick check
Use cases: where Galvanic Cells helps
- Homework: review the key idea behind Galvanic Cells before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Galvanic Cells without notes.
- Visual learning: play with the interactive lab to see how Galvanic Cells changes when you adjust its inputs.
- Teaching a friend: explain Galvanic Cells in your own words, then compare your version with the key ideas.
Chemistry explains medicine, food, cleaning products, fuels and building materials.
Frequently asked questions
What is Galvanic Cells?
Spontaneous redox reactions make electricity.
What will I learn in Galvanic Cells?
Anode oxidises, cathode reduces. Salt bridge keeps balance. Batteries are galvanic cells.
Is Galvanic Cells part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Galvanic Cells lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Galvanic Cells?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.