Organic chemistry Flashcards
What is organic chemistry about?
it is about compounds that contain carbon.
What is a hydrocarbon?
any compound that is formed from carbon and hydrogen atoms only.
What is the simpliest type of hydrocarbon you can get?
Alkanes, they have a general forumla of C n H 2n+2
What makes alkanes a homologous series?
they are a group of organic compounds that react in a similar way.
What is it called when each carbon atoms forms four single covalent bonds ( alkanes)?
saturated compounds.
What are the first four alkanes?
methane,ethane,propane,butane.
What happens as the length of the carbon chain changes?
the properties of the hydrocarbon changes
the shorter - the more runny it is - low boiling points,flammable
What is crude oil?
A fossil fuel.formed from the remains of plants and animals, mainly plankton , died millions of years ago and burried in mud.finite resources.
How do you seperature the different compounds in crude oil?
fractional distillation.
How does fractional distillation work?
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1) the oil is heated until most is turned into gas.gasses enter a fractionating colume.
2) in the column, theres a temperature gradient
3) longer hydrocarbons have high boiling points.condense back into liquids and drain out of the column near the bottom.shorter ones condense and drain out near the top.
Uses of crude oil?
1) fuel for most modern transport : cars, trains,planes
2) all products you get from crude oil are organic compounds
What does cracking mean?
splitting up long chain hydrocarbons,
breaking molecules down by heating them
Good things about short chain hydrocarbons.
flammable so make good fuels and are high in demand.
bad things about long chain hydrocarbons.
forms thick gloopy liquids like tar, not useful
different methods of cracking.
1)heat long chain hydrocarbons to vaportise them
vapour is passed over a hot powdered alumininium oxide catalyst
molecules split apart on the surface of the specks of catalyst-catalytic cracking
2)vapourise, mix them with steam and then heat them to a very high temperature - Steam cracking.
What are alkenes?
hydrocarbons which have double bond between two of the carbon atoms in their chain.
What bond do alkenes have?
C=C Double bond,
alkenes have two fewer hydrogens compared with alkanes containing the same number of carboin atoms- making them unsaturated.
What can incomplete combustion result in?
smoky yellow flame and less energy being released.
sometimes carbon and carbon monoxide can be produced-poisonous gas.
Alkenes react via addition reactions
the carbon carbon double bond will open up to leave a single bond and a new atom is added to each carbon
What is the addition of hydrogen known as?
hydrogenation
hydrogen can react with the double bonded carbons to open up the double and form the equivalent bond,saturated , alkane
What does steam react with alkenes to form?
alchohols.
when reacted with steam,water is added across the bond and an alcohol is formed.
For example, ethanol can be made by mixing ethene with steam and then passing it over a catalyst.
What is a functional group?
a group of atoms in a molecule that determines how that molecule typically reacts.
What are polymers?
long molecules formed when lots of small molecules called monomers join together - polymerisation
How to draw repeating unit of a polymer
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