Cyclic Hydrocarbons

compounds that contain hydrocarbon rings.

rings of 3 to 20 are found in nature5 and 6 are most abundantNaming:place the prefix cyclo out front

ex - cyclopentane general formula same as for an

alkene

Name each:

cyclooctane C8H16

cyclobutene C4H6

cyclohexane C6H12

same

Benzene C6H6

know this

Resonance - when one or more valid structures can be drawn. This makes a very stable molecule. Not as reactiveas other 6 carbon alkenes

Benzene is perfectly flat. Bending or twisting disrupts the double bonds. Chemist often use a circle to show the resonance in benzene.

termsAliphatic compounds

hydrocarbons that do not contain ringsArenes

unsaturated cyclic hydrocarbonsAromatic

old name for arenesused because arenes smell goodnow used to describe compounds that

have bonding like benzene

Naming compounds with benzene

If a hydrogen has been replaced with a substituent, name the substituent followed by the name benzene.

Examples -CH3 CH3

CH3

methylbenzene 1,2-dimthylbenzene

Naming compounds with benzene

If the benzene ring is a substituent of a carbon chain (an alkyl group) the name is changed to phenyl.

Example -

C-C-C-C-C

3-phenylpentane

cyclohexane

phenylbenzene

1-ethyl-3-propylbenzene

ethylbenzene

propylbenzene2-phenylpropane

Natural gas and petroleum

Natural gas and petroleum are 2 important fossil fuels

They contain mostly aliphatic hydrocarbons

What is the major component of natural gas?

It is the same gas we use in the lab and to heat your domicile (home).

Methane - CH4

Combustion reactions (a review)Complete Combustion

CxHy + O2 --> CO2 + H2OIncomplete Combustion

CxHy + O2 --> CO2 + H2O + C + CO

You will be expected to be able to write balanced equations for combustion reactions.

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A combustion reaction

PetroleumCrude oil is refined before it is used. We

just don’t use it directly out of the ground.It is separated on the physical property of

boiling points. This lab technique is called distillation.

The parts of crude oil are called fractions.The process of breaking large

hydrocarbons into smaller useful molecules is called cracking.

Petrochemicals - chemical used to make other products

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oil distillation

Coal - another important fossil fuel

Coal consists of condensed ring compounds of extremely high molar mass.

Due to the high proportion of these aromatic compound, coal leaves more soot. So, burning petroleum has an environmental advantage. However, you get more energy out of coal.

Coal contains sulfur which produces SO2 and SO3, which in turn makes acid rain.

Coal can be distilled to makecoal gas

hydrogen, methane, carbon monoxide all are flammable

coal tarpetrochemicals - benzene, toluene (methyl

benzene), napthalene, phenol, pitch Coke - a fuel used in industry

pure carbon - produces little smoke and burns with an intense heat

ammonia - cleaning product as well as being converted to ammonium sulfate for use as a fertilizer

Wouldn’t it be nice your car ran on water?watch video

Info for demo. Read it.