Agenda Review Check Combustion Prediction Combination Prediction

Balance and Identify Type Hydrogen peroxide  water and oxygen

Combustion Prediction 1. Octane + oxygen  B: 2:25:16:18 2C 8 H O 2  16CO H 2 O C: oxidized O: reduced

2. Propanol + oxygen  B: 2:9:6:8 2C 3 H 7 OH+ 9O 2  6CO 2 + 8H 2 O C: oxidized O: reduced

3. Ethene + oxygen  B: 2:5:4:2 2C 2 H 2 + 5O 2  4CO 2 + 2H 2 O C: oxidized O: reduced

4. 1-pentyne + oxygen  B: 1:7:5:4 C 5 H 8 + 7O 2  5CO 2 + 4H 2 O C: oxidized O: reduced

5. Ethanol + oxygen  B: 1:3:2:3 C 2 H 5 OH+ 3O 2  2CO 2 + 3H 2 O C: oxidized O: reduced

6. Pentane + oxygen  B: 1:8:5:6 C 5 H O 2  5CO 2 + 6H 2 O C: oxidized O: reduced

7. Benzene + oxygen  B: 2:15:12:6 2C 6 H O 2  12CO 2 + 6H 2 O C: oxidized O: reduced

Hydrogen’s charge remains constant at +1. Oxygen’s charge changes from 0 to -2 Carbon’s charge always becomes +4

Quiz Time There are 2 quizzes to take today Balancing Quiz 2 Identification of reaction types

Combination Prediction Date:

Identification of Combination Rxn from Reactants 2 elements May be 2 compounds, but one of which will be H 2 O.

Prediction of Products Type 1 Metal + nonmetal Balance charges Sodium reacts with chlorine Na + Cl 2  NaCl 2:1:2

Type 2 2 nonmetals Most of the time it will still work to balance charges. Technically supposed to balance number of e - so each atom has it’s complete octet. Hydrogen reacts with oxygen H 2 + O 2  H 2 O 2:1:2

Type 3 Nonmetal oxide (nonmetal bonded to O) + water Create an Acid Put all H first Nonmetal second All O last May need to reduce ratio Dinitrogen pentoxide reacts with water N 2 O 5 + H 2 O  H 2 N 2 O 6  HNO 3 1:1:2

Type 4 Metal oxide + water Create a BASE Put metal first Put OH next and balance charges Sodium oxide + water Na 2 O + H 2 O  NaOH 1:1:2

Combination as Redox Rxn If the charges change from side to side, the reaction is redox. Whenever elements are alone, they have no oxidation number – charge. Use PT to determine oxidation number when in a compound. Look back at the past examples to determine which were oxidized and reduced.

2Na + Cl 2  2NaCl Na: 0 to +1 oxidized Cl: 0 to –1 reduced

2H 2 + O 2  2H 2 O H: 0 to +1 O: 0 to -2

N 2 O 5 + H 2 O  2HNO 3 O:-2 to –2 N: +5 to +5 H: +1 to +1 Tricked ya! Not a redox rxn!

Na 2 O + H 2 O  NaOH Na: +1 to +1 O: -2 to –2 H: +1 to +1 Tricked ya! Not a redox rxn!

Redox Summary All Type 1 & 2 combination are redox rxn All type 3 & 4 are NOT!