Download - Cyclic Hydrocarbons
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.