Combustion Prediction Agenda  Writing  Review hydrocarbons  Reaction Prediction Combustion  Homework

Writing  Skip lines.  Complete sentences.  Should take about 2 min.

Writing  Given: 2Na + Cl 2  2NaCl  This is a combination rxn. How do you know?  How can you rule out each of the other rxn types?

Equations I 1. D: 2:2:1 2. DR: 1:1:2:1 3. C: 1:1:1 4. B: 2:9:6:6 5. C:2:5:2 6. SR: 2:2:2:1 7. B: 2:5:4:2 8. SR: DR: C: D: SR: DR: B: D:2.2.1

Combustion Prediction Date:

Hydrocarbon review  How many general parts do hydrocarbon names have? Three parts.  What are they? Prefix, root, and suffix.

Prefixes  What are the prefixes?  Meth-1 Hex-6  Eth-2Hept-7  Prop-3Oct-8  But-4Non-9  Pent-5Dec-10  How do we determine the prefix?  Count the number of carbons

Roots  What are the roots?  -ane, -ene, and -yne  How do we determine the roots?  Check the bonds between the carbons  -ane = single bonds  -ene = double bonds  -yne = triple bonds

Suffixes  What are the suffixes that we know?  -ol and -oic acid  How do we determine the suffixes?  Look at the functional group  -ol = alcohol (-OH)  -oic acid = carboxylic acid (-COOH)

Practice Naming  CH 3 CH 2 CH 3  CHCH  CH 3 CHCHCH 3  CH 3 CH 2 OH  CHCCOOH  Propane  Ethyne  Butene  Ethanol  Propynoic acid

Practice writing formulas  Octane  Butanoic acid  Ethene  Propyne  Ethynol  C 8 H 18  CH 3 CH 2 CH 2 COOH  CH 2 CH 2  CHCCH 3  CHCOH

Benzene  Its formula is C 6 H 6

Identification of Combustion Rxns From Reactants  HydroCarbon + O 2

Prediction of Products  ALWAYS CO 2 + H 2 O ALWAYS

Practice  Methane burns in oxygen gas.  Step 1 write the reactants  Step 2 write the products  Step 3 balance  Step 4 write rxn type and coefficient

Redox Rxn Rules  If the charges change from side to side, the reaction is redox.  Oxidation – the charge goes up  Reduction – the charge goes down  Whenever elements are alone, they have no oxidation number – charge.  Use PT to determine oxidation number when in a compound.

Methane (CH 4 ) reacts with oxygen  CH 4 + 2O 2  CO 2 + 2H 2 O  C: -4 to +4  H: +1 to +1  O: 0 to –2  C oxidized, O reduced

Ethane (C 2 H 6 ) reacts with oxygen  2C 2 H 6 + 7O 2  4CO 2 + 6H 2 O  C: -3 to +4  H: +1 to +1  O: 0 to –2  Carbon oxidized, oxygen reduced

Methanol (CH 3 OH) reacts with oxygen  2CH 3 OH + 3O 2  2CO 2 + 4H 2 O  C: -2 to +4  H: +1 to +1  O: -2 to –2 and 0 to –2  Carbon oxidized, oxygen reduced

ALWAYS REDOX  For comBustion reactions:  Carbon is ALWAYS oxidized!  Oxygen is ALWAYS reduced! ALWAYS