chem unit 3 redox

oxidation

loss of e

reduction

gain of e

oxidising agent/oxidant

causes oxidation by losing e, thus reduced

reducing agent/reductant

causes reduction by gaining e, thus oxidised

corrosion

metals reacting with atmospheric to form more stable compound

oxidation number increases

when oxidised

oxidation no. equivalent to

ion charge

oxidation no. of an element

0

oxygen oxidation no.

-2

sum of oxidation numbers

=0

sum of oxidation numbers for polyatomic ions

=charge

galvanic cell

chemical to electrical neg anode to pos cathode electron flow, spontaneous

electrolytic cell

non-spontaneous, electrical to chemical, pos anode to neg cathode electron flow, needs power source

salt bridge example

Na2SO4/KNO3

galvanic cell notation

molten electrolysis

container filled with liquid salts meltet down thus requires very high temp and energy to maintain high temperature and push electrons

equations higher up on table are more likely to

oxidise

aqueous electrolysis

dissolve ions into water causing water to ionise, 2 possible equations for oxidation/reduction, pick the two that are closest together and thus require least energy

monoprotic

donate or accept one H+ per molecule