Reaction of Hydrocarbons

Addition Reactions

A common type of reaction is an _______________ of alkenes and alkynes

Not alkanesWhere there are _______ and ______ bonds, the molecule does not contain the maximum number of __________ and is ____________

tripledouble

addition reaction

hydrogenunsaturated

Addition Reactions

Molecules are added across the ________ or ______ bondtriple

double

Addition Reactions

Addition Reactions

Addition Reactions

Which product do we get?

Minor

Major

Markovnikov’s Rule

When adding a binary acid (like HCl) to an asymmetric alkene, the hydrogen goes to the carbon with more __________

___________________The rich get richerhydrogens

Combustion Reactions

Another common reaction is combustionIf there is sufficient oxygen, then we have _________ combustioncomplete

1 C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)

Balancing Complete Combustion Example

• Write and balance the equation for the complete combustion of acetylene (ethyne).

• Formula for ethyne is:C2H2

• Reacts with oxygen gas: O2

• Products are carbon dioxide and water: CO2 H2O • Balance!

• 2 C2H2(g) + 5 O2 (g) 4 CO2 (g) + 2 H2O (g)

Combustion Reactions

If there is insufficient oxygen, then we have ___________ combustion

Instead of only carbon dioxide and water as products, we also form _______________ and _______________

incomplete

Hydrocarbon(g) + O2(g) → CO2(g) + H2O(g) + CO(g) + C(s)

carbon monoxideCarbon (soot)

Incomplete Combustion Reactions• Incomplete combustion occurs when there

is not enough oxygen present to fully burn up the hydrocarbon.

• The yellow flame of a candle indicates incomplete combustion because it is releasing carbon, which emits light energy in the yellow range of the visible spectrum.

• An incomplete combustion reaction can produce other compounds, often toxic.

• 2 C3H8 (g) + 7 O2 (g) 2 C(s) + 2 CO(g) + 2 CO2 (g) + 8 H2O (g)

Balancing Incomplete Reactions Example

• 2,2,4-trimethylpentane is a major component of gasoline. Write a possible equation for the incomplete combustion reaction.

• Formula for 2,2,4-tmp is: C8H18

• Mixes with oxygen gas: O2

• Products are carbon, carbon monoxide, carbon dioxide, and water: C, CO, CO2, H2O

• Balance!

2 C8H18 (g) + 15 O2 (g) 8 C(s) + 4 CO(g) + 4 CO2(g) + 18 H2O(l)