1. Introduction to Oxidation and Reduction
IB Chemistry Text
Green and Damji
TEXT 9.1 & 9.2
Copyright © The McGraw-Hill Companies, Inc.  Permission required for reproduction or display.

2. Types of Chemical Reactions ?
type of reaction ?
Mg(s) HCl (aq)  MgCl2 (aq) + H2 (g)
2. Pb(NO3)2 (aq) + 2 NaI (aq)  PbI2 (s) + 2 NaNO3 (aq)
2 H2O2 (aq)  O2 (g) H2O (g)
2 O2 (g) + CH4 (g)  CO2 (g) H2O (g)
H2 O (g)  O2 (g) + H2(g)

3. another way to classify Types of Chemical Reactions
A. Acid Base Reactions
B. Precipitation Reactions
C. Redox Reactions
CaO (s) + 2 HCl (aq)  CaCl2 (aq) H2O (l)
H3PO4 (aq) NaOH (aq)  Na3PO4 (aq) H2O (l)
Pb(NO3)2 (aq) + 2NaI (aq) PbI2 (s) + 2NaNO3 (aq)
which can be shortened to…Pb2+ + 2I PbI2 (s)
2 Zn (s) + I2 (s) ZnI2 (aq)
2 Zn (s) + I2 (s) Zn2+ (aq) + 2 I- (aq)

4. Classify the following reactions as AB/PPT/RedOx
Ca2+ + CO CaCO3
________________
NH3 + H NH4+
________________
Zn + 2HCl ZnCl2 + H2
________________
Ca + F CaF2
________________
4.4

5. Oxidation-Reduction Reactions
(electron transfer reactions)
2Mg + O MgO
What is happening in this reaction?
oxidation – loss of electrons:
reduction – gain of electrons:
4.4

6. Helpful Mneumonics
LEO the lion goes GER Loss of Electrons is Oxidation Gain of Electrons is Reduction OIL RIG Oxidation is the Loss of electrons Reduction is the Gain of electrons

7. Oxidation number Na, Be, K, Pb, H2, O2, P4 =
The charge the atom would have in a molecule (or an
ionic compound) if electrons were completely transferred
to the more electronegative element.
Free elements (uncombined state) have an oxidation number of zero.
Na, Be, K, Pb, H2, O2, P4 =
In monatomic ions, the oxidation number is equal to the charge on the ion.
Li+, Li = ; Fe3+, Fe = ; O2-, O =
The oxidation number of oxygen is usually In H2O2 and O22- it is .
4.4

8. HCO3- O = ____ H = ____ 3x(-2) + 1 + ? = -1 C = ____
The oxidation number of hydrogen is____except when it is bonded to metals in binary compounds. In these cases, its oxidation number is____.
Group 1 metals are____, Group 2 metals are____and fluorine is always____.
6. The sum of the oxidation numbers of all the atoms in a molecule or ion is equal to the charge on the molecule or ion.
7. Oxidation numbers do not have to be integers. Oxidation number of oxygen in the superoxide ion, O2-, is ____.
HCO3-
Oxidation numbers of all the elements in HCO3- ?
O = ____
H = ____
3x(-2) ? = -1
C = ____
4.4

9. The oxidation numbers of elements in their compounds
The periodic table in your planner includes the most common oxidation numbers!
4.4

10. I F7 F = ____ 7x(____) + ? = 0 I = ____ K2 Cr2 O7 Na I O3 Na = ____
What are the oxidation numbers of all the elements in the following compounds ?
F = ____
7x(____) + ? = 0
I = ____
K2 Cr2 O7
Na I O3
Na = ____
O = ____
O = ____
K = ____
3x(____) + ____ + ? = 0
7x(__) + 2x(__) + 2x(?) = 0
I = ____
Cr = ____
4.4

11. More to know…
An increase in oxidation number is oxidation. A decrease in oxidation number is reduction. The substance that is oxidized (loses e-; ox # increases) is called the reducing agent. The substance that is reduced (gains e-; ox # decreases)

12. Zn (s) + CuSO4 (aq) ZnSO4 (aq) + Cu (s) ox: red:
ttl:
____ is oxidized - is reducing agent
____ is reduced - is oxidizing agent
4.4

13. Copper wire reacts with silver nitrate to form silver metal.
What is the oxidizing agent in the reaction?
ox:
red:
ttl:
____ is oxidized - is reducing agent
____ is reduced - is oxidizing agent
4.4

14. Types of Oxidation-Reduction Reactions
Combination Reaction (aka Synthesis)
A + B C +3 -1
2Al + 3Br AlBr3
Decomposition Reaction
C A + B +1 +5 -2 +1 -1
2KClO KCl + 3O2
4.4

15. Types of Oxidation-Reduction Reactions
Combustion Reaction
A + O B +4 -2
S + O SO2
2Mg + O MgO +2 -2
4.4

16. Types of Oxidation-Reduction Reactions
Single Displacement Reaction
A + BC AC + B +1 +2
Sr + 2H2O Sr(OH)2 + H2
Hydrogen Displacement +4 +2
TiCl4 + 2Mg Ti + 2MgCl2
Metal Displacement -1 -1
Cl2 + 2KBr KCl + Br2
Halogen Displacement
4.4

17. Types of Oxidation-Reduction Reactions
Disproportionation Reaction
Element is simultaneously oxidized and reduced. +1 -1
Cl2 + 2 OH ClO- + Cl- + H2O
Chlorine Chemistry
4.4

18. Chemistry in Action: Metals from the Sea
Redox or not?
CaCO3 (s) CaO (s) + CO2 (g)
_______________
CaO (s) + H2O (l) Ca2+ (aq) + 2OH (aq) -
_______________
Mg2+ (aq) + 2OH (aq) Mg(OH)2 (s) -
_______________
____________
Mg(OH)2 (s) + 2HCl (aq) MgCl2 (aq) + 2H2O (l)
_______________
MgCl2 (aq) Mg (s) + Cl2 (g)
Write half reactions for one of the redox reactions above:
ox:
red: