Redox Reactions

Lecture 4.3

Oxidation-Reduction (Redox) =

Oxidation =

Ex:

Fe(s) Fe⁺² (aq) + 2 e^-

Oxidized

Reduction =

Ex:

Cu⁺²(aq) +2 e^- Cu(s)

Reduced

OIL RIG

“Oxidation Is Loss, Reduction Is Gain”

Oxidizing Agent =

Reducing Agent =

Cu⁺²(aq) + Fe(s) Fe⁺² (aq) + Cu(s)

Oxidized, Reducing Agent

Reduced, Oxidizing Agent

Oxidation-Reduction (Redox)

Oxidation-Reduction (Redox)

Ex: In the following reaction identify the: Substance being oxidized, substance being reduced, oxidizing agent, and reducing agent.

Na(s) + Ag⁺(aq) Na⁺ (aq) + Ag(s)

Assigning Oxidation Numbers

1. Elements in their elemental state

(or bonds between the same element) =

Ex: Fe(s) = 0

2) Monoatomic Ions = their charge

Ex: Cu⁺² = N^-3 =

3) Oxygen in nearly all compounds =

(except peroxides like H₂O₂ where it = )

4) Family I in compounds =

Ex: NaCl Na =

5) Family II in compounds =

Ex: CaCO₃ Ca =

Ex: N₂ = 0

Assigning Oxidation Numbers

6) Fluorine =

7) All other Halogens = (unless bound to oxygen or another halogen)

8) H = , when bound to a non-metal

Ex: NaCl Na =

Ex: BrCl Br = Cl =

Ex: NH₃ H=

9) H = , when bound to a metal

Ex: CaH₂ H= -

Assigning Oxidation Numbers

10) Sum of all oxidation #’s in a compound = 0

Ex: NaCl Na = Cl =

11) Sum of all oxidation #’s in a polyatomic ion = charge of ion

Ex: Na₂SO₄

Ex: H₂PO₄^-

Ex: Ca(NO₃)₂