flask Redox & Electrochemistry
Redox reactions move electrons, and electrochemistry harnesses that movement in batteries or drives it with electricity in electrolysis. From corrosion to fuel cells, this topic connects chemistry to energy technology.
What you will learn
- Assign oxidation states
- Identify oxidizing and reducing agents
- Balance redox equations
- Calculate cell potentials
- Apply the Nernst equation
Beginner concepts
Batteries: primary, secondary, and how they work
Primary batteries are single-use, secondary batteries recharge. Tour the Leclanché dry cell, the lead-acid car battery, and the lithium-ion chemistry in modern devices.
Oxidation vs reduction: what each one really means
Oxidation is loss of electrons; reduction is gain of electrons. Learn the OIL RIG and LEO GER mnemonics and why the two processes always occur together.
Introductory College concepts
Calculating standard cell potential
Cell potential is E°cell = E°cathode − E°anode, both as reductions. Work the Daniell cell (+1.10 V) and connect the sign to spontaneity through ΔG° = −nFE°.
Electrolysis and Faraday's laws
Faraday's laws link electric charge to chemical amount: Q = It and moles of electrons = Q/F. Work a full copper-plating calculation and compare molten vs aqueous NaCl products.
Balancing redox reactions with the half-reaction method
Master the half-reaction method for balancing redox equations in acidic solution, with a fully worked and verified permanganate–iron(II) example.
Standard reduction potentials
Standard reduction potentials measure how strongly a species gains electrons relative to the hydrogen electrode (0.00 V). Learn to read the table and rank oxidizers.
High School concepts
Corrosion and rusting
Rusting is iron's slow galvanic cell in action. Learn the chemistry of rust formation and the four main prevention strategies: coatings, galvanization, sacrificial anodes, and cathodic protection.
Electrolytic cells
Electrolytic cells use external electrical power to drive nonspontaneous redox reactions — the reverse of galvanic cells. See how electroplating and electrorefining work.
Galvanic (voltaic) cells
Explore the galvanic (voltaic) cell: the Daniell cell, anode and cathode roles, the salt bridge, and how electron flow through a wire powers a circuit.
Oxidation states: rules for assigning them
Learn the standard rules for assigning oxidation states to atoms in compounds and ions, with fully worked examples including sulfuric acid and permanganate.
Oxidizing and reducing agents
An oxidizing agent is reduced while it oxidizes something else, and a reducing agent is oxidized while it reduces something else. Meet the common examples of each.
Intermediate concepts
Formulas
Standard Cell Potential
E(cell) = E(cathode) - E(anode), both as standard reduction potentials
Faraday's Law of Electrolysis
mass = (current x time x molar mass) / (n x Faraday constant); moles of electrons = I x t / F
Nernst Equation
E = E(standard) - (RT/nF) x ln Q ; at 25 C: E = E(standard) - (0.0592 V / n) x log Q