Lecture 5
First the isobutane challenge!
The boiling point of n-butane is -0.5oC whereas the boiling point of isobutane is -11.6oC. As I predicted isobutane has the lower boiling point.
We examined the solutions that are natural gas and oil. Although both of these solutions are largely composed of carbon (by weight) when viewed in terms of atomic compositions we see that the fuels are hydrogen-rich compared to coal.
The compounds are greatest interest to us are hydrocarbons (those organic compounds that consist only of carbon and hydrogen).
- n-alkanes (normal-alkanes) (straight chain hydrocarbons) such as
- branched or iso-alkanes
- 2,2,4-trimethylpentane C8H18 (the is the famous iso-octane)(for example, note that it retains the CnH2n+2 formula)
- cyclic hydrocarbons
- cyclopentane C5H10
- cyclohexane C6H12
- 1,3-dimethylcyclopentane C7H14
- aromatics
- benzene C6H6
- toluene C7H8
- xylene C8H10 (meta-xylene, ortho-xylene, para-xylene)
You don’t have to remember these formulae but you should remember that all these things are different hydrocarbons. The small ones (methane, ethane and propane) are in natural gas and the larger ones (and more) are in crude oil.
Natural gases will also include things like helium and carbon dioxide. In fact some gas accumulations consist almost completely of carbon dioxide. We get all our helium and some of the carbon dioxide used in industrial and commercial applications from natural gas sources.
Posted: September 3rd, 2009 under Petroleum, Study Guide, Study Guide Exam 1, Uncategorized.