redox+reactions+in+aqueous+solution


 * //Redox reactions in aqueous solution// **


 * Videos**

Redox reactions and changes in oxidation state || media type="custom" key="24089674" Assigning oxidation numbers || media type="custom" key="24089716" Determining half-reactions ||
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Galvanic cells + electrochemical series, evidence for electron transfer || media type="custom" key="24090214" Introduction to metal corrosion || media type="custom" key="24090272" Wet corrosion of iron ||
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Impressed current protection from corrosion || media type="custom" key="24090342" Galvanic/sacrificial protection from corrosion ||
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 * Common misconceptions:**
 * Electrons enter the solution from the cathode, travel through the solutions and the salt bridge, and emerge at the anode to complete the circuit.
 * Cations in the salt bridge and the electrolyte accept electrons and transfer them from the cathode to the anode.
 * Cations and anions move until their concentrations are uniform.
 * The anode is positively charged because it has lost electrons; the cathode is negatively charged because it has gained electrons.
 * The oxidant is itself oxidised and the reductant is reduced.
 * Oxidation always involves oxygen.


 * Interesting facts:**
 * Always remember OIL RIG when thinking about electrons (OXIDATION IS LOSS, REDUCTION IS GAIN).
 * The oxidant (or oxidising agent/oxidiser) gains electrons and is therefore itself reduced.
 * The reductant (or reducing agent/reducer) loses electrons and is therefore itself oxidised.
 * Galvanic cells are named after the Italian scientist Luigi Galvani, who first made the connection between chemical reactions and electricity.
 * Oxidation takes place at the anode, reduction occurs at the cathode.
 * Ions flow through the salt bridge. Its function is to complete the circuit and balance the overall charge. Anions in the salt bridge move to the half cell that contains the anode and cations move to the cathodic half cell. Therefore, the electrons move from anode to cathode via the wire of the external circuit, not the salt bridge.
 * Wet corrosion (corrosion that involves water) operates like a mini galvanic cell, where electrons are transferred through the iron and ions flow through the water droplets.
 * Dry corrosion refers to the oxidation of a metal by oxygen.


 * Resources:**
 * Microscale redox chemistry experiment from the Royal Society of Chemistry.
 * Erin Brockovich Assessment Task from TES.
 * Oxidation/reduction reactions from Chemistry Lecture Notes.
 * Oxidation/reduction and electrochemistry virtual lab from the ChemCollective.