Organic Chemistry Flashcards
How does fractional distillation work
The column is hot at the bottom and cool at the top so substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to stop
How do hydrocarbons properties change as you go up the fractionating column
- lower boiling points; less intermolecular bonds 2. lower viscosity as less molecules; less intermolecular bonds to tangle 3. less flammability; bigger hydrocarbons have more soot
Define a hydrocarbon
Hydrocarbon- a molecule that only contains hydrogen and carbon
What are the endings for Alkanes
‘ane’
What are the first 4 structural formulas for alkanes
- Methane CH4 - Ethane C2H6 - Propane C3H8 - Butane C4H10
What is the general formula for Alkenes
CnH2n+2
What is the difference between structural formulas, skeletal formula and strutured formulas
Structural is the pure numbers and elements Skeletal only use dots and sticks Strctures uses lines and elements
Define Isomers
Isomers have the same molecular formula but a different structure e.g. butane and methyl propane
How are isomers named
Largest carbon chain/ where functional groups are added
How is crude oil formed
Dead biomass formed thick layers of sediment on sea beds under heat and pressure in anaerobic conditions decay occurs; oil formed 50-250 million years
What are the conditions needed for formation of crude oil
-animal remains -high temp. and pressure -anaerobic conditions + millions of years
What sort of alkanes are in demand
Shorter alkanes are in very high demand and larger are less in demand as they are harder to ignite and more viscous
What is cracking
Larger alkanes are cracked to form alkanes and alkenes Long alkanes –> shorter alkanes + alkenes
What is catalytic cracking
vaporise alkanes and pass them over a hot catalyst; Al2O3 (600-700C)
What is steam cracking
you vaporise alkanes, mix them with steam and then heat to a high temp. Shown by bromine water going from orange to colourless
What are alkenes
a homologous series of unsaturated hydrocarbons with the functional group C=C double bond. End in ‘ene’