7 Organic Flashcards
Hydrocarbon
Compound formed from only hydrogen and carbon
Explain alkanes
Alkanes are a homologous series so they all react similarly. Alkanes are saturated meaning each carbon has filled out their shells. Alkanes end in ane and have single bonds e.g methane
Relationship between viscoity/flammability and chain length
The vicosity in a hydrocarbon increases with longer chain due to higher IMF which makes the solution more thick.
The shorter the chain the more flammable a hydrocarbon becomes as the boiling point is lower and has lower IMF
What is crude oil and how is it formed
Crude oil is a fossil fuel composing of mixtures of hydrocarbons. They are formed from the remains of plants and plankton that died and compressed in mud with high temperature and pressure.
Paper
Explain the process of fractional distillation
A furnace is heated to a very high temperature
Then crude oil is flowed through the tube into a fractioning column
The top of the fractioning column is cool. So shorter chain hydrocarbons will condense at the top where it is cooler.
The bottom is hot. So longer chain hydrocarbons will condense at the bottom at much higher temps due to stronger IMF.
This is useful as shorter chain hydrocarbons can be used as fuels as they are more flammable.
Explain cracking and what is it
Cracking is a thermal decomposition reaction.
First heat long chain hydrocarbons to vaporise them
Pass the vapour over a catalyst
The long chain molecules will split into an alkane and alkene.
There is another type of cracking where you pass them over steam.
Alkene
An unsaturated hydrocarbon that has a double bond between two of the carbon atoms
1 property of alkenes
More reactive than alkanes as they have a double bond that can open up to form a single bond allowing them to be part of addition reactions.
Why arent alkenes used as fuels
Alkenes aren’t used as fuels because they undergo incomplete combustion which produces CO2+H2O+ C or CO those products are harmful to the enviroment and poisonous. Lesss energy is released.
What are addition reactions
One molecule reacts with another to form one larger molecule with no products.
Explain the 3 addition reactions with alkenes
Hydrogenation- The addition of hydrogen to alkenes which opens up the double bond allowing the alkene to change into an alkane thats saturated.
Hydration-When alkenes react with steam they produce alcohols as H2O is added
Halogens-Can be added to alkenes to open up the bond like bromine
Bromine water test
Tests for alkenes turns orange to colourlous as it bonds to the alkene
