Alkanes and Halogenalkanes lol
No description yet. This curated deck is ready for daily study.
Card preview (24)
What do alkenes contain?
Only hydrogen and carbon do hydrocarbons
How many bonds does every carbon atom in an alkane make?
Four single bonds with other atoms so impossible for carbon to make more than four bonds so alkenes are saturated (only contain single bonds)
Alkanes first four
Methane Ethane Propane Butane
What else can you get like alkanes?
Cycloalkanes but have different general formula CnH2n assuming only one ring but still saturated
Petroleum what is it?
Crude oil Mixture of hydrocarbons (mainly alkanes ranging from small alkanes like pentane to massive alkanes of more than 50 carbons.
Is crude oil useful?
Not as it is it needs to undergo fractional distillation
Fractional distillation step 1
1) first the crude oil is vaporised at about 350 degrees
Fractional distillation step 2
Vaporised crude oil goes into a fractional column and rises up through the trays. The largest hydrocarbons don’t vaporise at all, because their boiling points are too high- they just run to the bottom and form a gooey residue
Fractional distillation step 3
As crude oil vapour goes up the fractionating column it gets cooler because alkane molecules have different chain lengths they have different boiling points so each fraction condenses at a different temperature. The fractions are drawn off at different levels in the column. They’re drawn off as gases at the top of the column
Gases
1-4 carbons Liquefied petroleum gas (LPG) camping gas
40 degrees
Petrol 5-12 carbons Petrol
110 degrees
Naphtha 7-14 carbons Processed to make petrochemicals
180 degrees
Kerosene (paraffin) 11-15 carbons Jet fuels. Petrochemicals, central heating
250 degrees
Gas oil (diesel) 15-19 carbons Diesel fuel, central heating fuel
340 degrees
Mineral oil (lubricating) 20-30 carbons Lubricating oil
Residue
Fuel oil, 30-40 carbons, ships, power stations wax, grease, 40-50 candles lubrication bitumen 50+ roofing, road surfacing
What’s most in demand from crude oil?
Lighter fractions of crude oil like petrol and naphtha Heavier stuff like bitumen So more expensive to get stuff in demand
How is this demand met?
Less popular heavier fractions are cracked. Cracking is breaking long-carbon chain alkanes into smaller hydrocarbons (including alkenes) involved breaking c-c bonds
Can you choose a certain length to crack to?
No where the chain breaks is random so you’ll get a different mixture of products everything you crack a hydrocarbon
General formula for alkane a?
CnH2n+2
What do alkenes contain?
Only hydrogen and carbon do hydrocarbons
How many bonds does every carbon atom in an alkane make?
Four single bonds with other atoms so impossible for carbon to make more than four bonds so alkenes are saturated (only contain single bonds)
Alkanes first four
Methane Ethane Propane Butane
What else can you get like alkanes?
Cycloalkanes but have different general formula CnH2n assuming only one ring but still saturated