Activity Series

●Used to determine the products of a single replacement reaction–An element higher in the series will replace a lower element in a compound●Zn(s) + CuCl2(aq) → ZnCl2(aq) + Cu

●Determine what is oxidized and what is reduced●What conclusion can you make about oxidation and replacement?

Writing Half Reactions

●CH4 + 2O2 → CO2 + 2H2O

●oxidation: CH4 → CO2

●reduction: 2O2 → 2H2O

●Zn + 2HCl → ZnCl2 + H2

●ox: Zn → Zn+2 + 2e-

●red: 2e- + 2H+ → H2

●overall: Zn + 2H+ → Zn+2 + H2

Balancing Redox by Half Reaction Method●1. write half reaction for oxidation reduction–Do not include polyatomic ions that do not change●2. For each half reaction:–Balance all elements except H and O–Balance O by adding H2O–Balance H by adding H+–Balance charge using electrons●3 if necessary, multiply one or both of the balanced half reactions to equalize the number of electrons in the 2 half reactions●4. add half reactions – cancel identical species on opposite sides of the arrow●5. check elements and charges are balanced