Oxidation = loss of electrons
Reduction = gain of electrons
(they occur together)
Helpful to write them separately = half reactions
Include reactant being oxidized or reduced
Electrons lost = products
Electrons gain = reactants
EX.
Zn(s) + 2H+ (aq) → Zn2+ (aq) + H2(g)
Zinc oxidized to Zn2+
Half reaction: Zn → Zn2+ + 2e− (balanced in terms of zinc atoms) (there is account for loss of 2 electrons)
Hydrogen is reduced
Half reaction: 2H+ + 2e− → H2 (balanced; charge is 0)
OVERALL REACTION is sum of half reactions
Electrons cancel out.
*in balanced redox reactions electrons have to cancel out exactly
Redox reactions = each individual half reaction and then combining the two balanced half reactions.
Sometimes a half reaction must have all of its coefficients multiplied by some integer for all the electrons to cancel.
EX. BELOW
Write and balance the redox reaction that has silver ions and aluminum metal as reactants and silver metal and aluminum ions as products.
**SOLUTION BELOW…TOO LAZY TO REWRITE..SORRY..GOTTA READ:(