6 Alkanes

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  • Created by: Naana
  • Created on: 26-02-15 14:25
What is an alkane?
They are saturated hydrocarbons. Contain only single carbon-carbon bonds/ carbon-hydrogen bonds
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Why are alkanes very important?
Used as starting materials for a range of other compounds.
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What are the physical properties of alkanes?
Non polar- similar electronegativities between carbon and hydrogen. Boiling points increase as hydrocarbon chain length increases. Insoluble in water
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Do alkanes chemically react?
They are relatively unreactive- have strong c-c and c-h bonds. However they will react with halogens under suitable conditions. Also, burn in excess oxygen to form co2 and h20
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What does crude oil consist of?
It a mixture of mostly alkanes, both unbranched and branched
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How is crude oil separated into useful fractions on an industrial scale?
By a process called fractional distillation. Heat the crude oil and collect the fractions that boil over different ranges of temperatures. Each fraction is a mixture of hydrocarbons of similar chain length and similar chemical properties
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What is cracking?
When long hydrocarbon chains are broken into shorter lengths by breaking carbon-carbon bonds
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What are the economic reasons for cracking?
The shorter C chains e.g. naphtha for petrol and chemical industry are in huge demand than larger fractions. To supply demand for shorter fractions, larger hydrocarbons are cracked. The products of cracking are more valuable
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What is a fuel?
Substances that release heat energy when energy they undergo combustion. Also store huge amount of energy for a small amount of weight
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Why are alkane’s good fuels?
When alkanes burn, combustion reactions give out heat. Have large negative enthalpy of combustion. The more carbons present, the greater the heat output
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Other cards in this set

Card 2

Front

Why are alkanes very important?

Back

Used as starting materials for a range of other compounds.

Card 3

Front

What are the physical properties of alkanes?

Back

Preview of the front of card 3

Card 4

Front

Do alkanes chemically react?

Back

Preview of the front of card 4

Card 5

Front

What does crude oil consist of?

Back

Preview of the front of card 5
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