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Name: _ Asian we Recitation Day, Time: _\tie dA 2D CHM 116 Recitation 14 A spontaneous oxidation-reduction (redox) reaction involves the transfer of one or more electrons from one chemical species to another. Oxidation refers to a reaction in which electron(s) are given of f by a Species; while reduction refers to a reaction in which electron(s) are gained by a species. A redox reaction is therefore a couple of oxidation and reduction. Ina voltaic (or galvanic) cell, electron transfer takes place through an external pathway (eg., a copper wire, which has minimal electrical resistance as opposed to through an aqueous solution), There are two separate cells, where the oxidation half-reaction takes place in ‘one half-cell (called the anode), and the reduction half-reaction takes place in the other half-cell (called the cathode). The “free energy” released (by having AG°< 0) in the spontaneous redox reaction is converted to electrical work (a usable form of energy) while an electrical current is driven by a positive potential difference (or voltage), Hence, AG° = - n F E° where E° > 0 is the voltage of the voltaic cell. n and F in the equation are constants. Zs) —> Zn** (ag) + 2e> Cu?* (aq) + 2e° —> Culs) 1. Examine the reactions that Zn and Cu undergo separately in their respective half-cells. * Write down the reaction for Zn. You can simply copy it from above. ZnS} —9 Inhaqy © 207 * Is Zn losing or gaining electrons? \o ang * Is Zn getting oxidized or reduced? Ox\ darnon, 
