1. Oxidation-Reduction Reactions Ch 19 p. 591
Name the five reaction types you already know.
Synthesis, decomposition, combustion , single-replacement, double-replacement.
Now investigate a special characteristic
Transfer of electrons from one atom to another.
Oxidation-Reduction Reactions Ch 19 p. 591

3. Oxidation-Reduction Reactions Ch 19 p. 591

8. Oxidation-Reduction Reactions Ch 19 p. 591
Rules for assigning oxidation# in a chemical reaction
Atoms of pure substances have oxidations of zero.
Ex. Au, Fe, Ag, O2
2. Florine in compounds always -1
3. Oxygen almost always has -2 in compounds except when it is in a peroxide H2O2, when the oxygen oxidation number is -1.
4. Hydrogen has an oxidation number of +1 in all compounds containing elements that are more-electronegative than it; it has an ox# of -1 in compounds with metals.

9. 5. In polyatomics the sum of oxidation# is equal to charge of ion.
Ex. Nitrate (NO3) -1 Nitrite (NO2) -1
Sulfate (SO4) -2 Phosphate (PO4) -3
In neutral compounds the sum of ox# equal zero
Ex NaCl K2S H2O
Element on right stays normal Oxidation number …/esselman

10. 1. UF HNO3
2. H2SO P4O10
3. ClO HClO3
4. HCl N2O5
5. CF GeCl2
6. PCl3
7. SO2

11. Identifying Oxidation & Reduction Reacton
“Moving electrons from one to another”
“The element changes oxidation number”
A substance that loses an e-
becomes more positive so it is oxidized
( rusting….batteries….combustion…..electroplating
A substance that gains an e-
becomes more negative so it is reduced
OIL RIG

12. OIL Oxidized Is Lost electron RIG Reduced Is Gained electron
“You cannot have one without the other”
For short, sometimes Chemist refer to these reactions as a “ redox reaction “.

13. Identifying reduction/ oxidation equations
1. assign all Oxidation numbers
2. did any numbers change
3. IF YES then Redox
will have both oil/rig
Practice sheet ….p595…#2, #3.

14. Identify Reduction/Oxidation Equations
1. H Cl HCl
2. NaOH HCl NaCl H20
3. 8HNO H2S NO H H2SO4
4. KNO KNO O2

15. H CuO Cu H2O
CH O CO H2O
2Al CuCl AlCl Cu
8. 2HgO Hg O2

16. SnCl FeCl FeCl SnCl2
2NH4Cl +Ca(OH) NH H2O CaCl2
11. 2HNO3 +3H2S NO H2O S

17. stop