C7-Organic chemistry Flashcards
What is a hydrocarbon
This only contains hydrogen and carbon atoms
What is crude oil
A finite resource formed over millions of years
– remains of tiny sea creatures – plankton which have been all the high pressure and temperature with no oxygen
– mixture of all hydrocarbons made it different Lengths
What is an alkane
C – C single bonds
What are the first four alkanes
Methane – CH4
Ethane-C2H6
Propane – C3H8
Butane – C4H10
What is the formula for an alkane
Cn H2n+2
What happens as hydrocarbon chains get longer
The longer chains are less flammable, less volatile, more gloopy
– longer chains have a higher boiling point and therefore a worse as fuse
When does complete combustion occur
When there is plenty of oxygen
Hydrocarbon + oxygen—>Carbon dioxide +water +Energy
What does fractional distillation do
It separates hydrocarbons of different fractions
What are the steps in fractional distillation of hydrocarbons
1) crude oil is a mixture of hydrocarbons of different chain lengths and boiling points
2) evaporate the mixture for heating
3) Once it turns into gas the gases into a fractionating column Where there is a temperature gradient (it’s at the bottom and gets cool as you go up)
4) The longer hydrocarbons with higher boiling points will condense into liquids and drying out early on, when then at the bottom – the shorter hydrocarbons have lower boiling points and condenser and drain out much later on near the top where it is cooler
5) You end up with the crude oil mixture separated out into different fractions
What is the order for fractional distillation of crude oil
Refinery gases-Rhino George Gasoline-going Naphtha-north Kerosene-Korea Diesel oil-definitely over Fuel -France Residue-realistically
What is an alkene
C=C Double bonds
– they are more reactive
What are uses of the different fractions produced by fractional distillation
– Fuel
– petrochemical industry – feedstock to make new compounds e.g. lubricants
What is cracking
Split up longer chain hydrocarbons
Why do we use cracking
To get the short chain hydrocarbons which are useful for fuse and are in high demand although there is a short supply of them
What are the two methods of cracking
– Catalytic cracking
– steam cracking
