1. LO: I know how to write redox equations.

2. A redox equation is formed by joining two ion-electron equations:
An equation (top)
oxidation
A equation (bottom)
reduction
Before combining they must be balanced for electrons. 2
Na Na+ + e- 2 2
F2 + 2e F-
2Na + F Na+ + 2F-
LO: I know how to write redox equations.

3. 2MnO4-+ 5SO32-+ 6H+ 2Mn2++ 5SO42-+ 3H2O
Example 2: 5
SO H2O SO H+ + e- 5 5 10 2 10 2 2
MnO H+ + e Mn H2O 16 8 10 5 2 8 4
2MnO4-+ 5SO32-+ 6H Mn2++ 5SO42-+ 3H2O
LO: I know how to write redox equations.

4. 11.2.2 Ion-electron equations from scratch
LO: I know how to write ion-electron equations from scratch.

5. What is the ion-electron equation for the reduction of acidified dichromate ions, Cr2O72-(aq), to chromium (III) ions, Cr3+(aq), in aqueous solution?
LO: I know how to write ion-electron equations from scratch.

6. 1. Balance the non-oxygen element:
Cr2O72-(aq)
Cr3+(aq) 2
2. Balance oxygen using water: 2
Cr2O72-(aq)
Cr3+(aq)
+ 7H2O(l)
3. Balance hydrogen using H+(aq) ions: 2
Cr2O72-(aq)
Cr3+(aq)
+ 7H2O(l)
+ 14H+(aq)
4. Balance charge using electrons: 2
Cr2O72-(aq)
Cr3+(aq)
+ 7H2O(l)
+ 14H+(aq)
+ 6e-
LO: I know how to write ion-electron equations from scratch.