Electrochemistry

=Electrochemistry=

Displacement Reaction
- A reaction in which metal converts the ion of another metal to the neutral atom (Remember: **More** reactive displaces **less** reactive)

Oxidation-Reduction Equation
- Known also as Redox reactions and electron transfer reactions, Redox reaction is a reaction where electrons are transferred between species

Oxidation
- Loss of electrons (OIL)
 * **Oxidant**
 * "Electron acceptor", causes **oxidation** and is **reduced** in the **process**

Reduction
- Gain of electrons (RIG)
 * **Reductant**
 * "Electron donor", causes **reduction** and is **oxidised** in the process

Oxidation State
- an indicator of the degree of oxidation of an atom in a chemical compound - in monatomic ions, it will be the valence of the ion - in polyatomic ions, it will be overall sum of charge (usually indicated by the superscript of its charge)

**Fuel Cell**
- Electric cell that converts chemical energy of a fuel (i.e. Hydrogen) into electrical energy

Galvanic Cell
- An "electron pump", it pumps electrons out of the **negative** terminal into the external circuit and "sucks" them back into the **positive** terminal, this occurs due to the redox equation - Named for a device in which a chemical reaction occurs in such a way that it generates electricity

Battery
- Several cells joined together in a common outer casing

Electrode
- Conductor of a cell, connected to an external circuit

Anode
- Electrode at which **Oxidation** occurs, negative terminal

Cathode
- Electrode at which **Reduction** occurs, positive terminal

Potential Difference
- Measured in Volts (V) or Joules per Coloumb (J/C) is the difference in electrical potential energy per unit charge between two points. It is equal to the work required, per unit of charge, against a static electric field to move the charge between two points

Electrolyte
- A substance which in solution or molten conducts electricity

Salt Bridge
- Used to connect the oxdidation and reduction half cells, usually made of Potassium Nitrate. - It used to allow the migration of ions to occur (and to keep the charge balanced in both cells so that the process can continue) - To pick an effective electrolyte to be used in the salt bridge, it needs to **not react with any ions in the solutions it is connecting** and **not form any precipitates with other ions**

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Redox Half Equations
Redox half equations are present in displacement reactions where electrons are passed from one atom to an ion.

Important things to remember: A reductant is **gaining electrons** and **itself is oxidised** An oxidatidant is **losing electrons** and **itself is reduced**