✅Chemistry PAPER2 organic chemistry Flashcards
What is a hydrocarbon
Compounds that form from carbon and hydrocarbon atoms
What are alkanes
A type of hydrocarbon
What are the first four alkanes
Methane, Ethan, propane, butane
What is crude oil
A mixture of different hydrocarbons it is a finite resource and a fossil fuel found in rocks
Why is crude oil important
It is an important source of raw materials for chemical reactions it can be used to make plastics and fuels
What is the chemical formula for methane
CH4
What is the chemical formula for Ethane
C2H6
What is the chemical formula for propane
C3H8
What is the chemical formula for butane
C4H10
What are examples of fossil fuels
Coal oil gas
What can crude oil be used for
Provides fuels for transport for example cars, diesel oil heavy fuel oil LPG these all come from crude oil
What are petrochemicals
Petrochemicals or compounds that come from crude oil
What do the petrochemical industry use for the compound from crude oil
Polymers, solvent, lubricant, detergent
What happens if the length in the carbon chain changes
The properties of the hydrocarbons will change, shorter hydrocarbon chain, More runny, Lower boiling point, more flammable
What method is used to separate crude oil
Fractional distillation
What does saturated mean
It has too many I can’t have anymore
How many hydrogens will an alkane have with 10 carbons
4 hydrogens
What crude oil be used to make
Fuels, plastics
What is the chemical that makes crude oil
Hydrocarbon
What are organic compounds
Compounds that are containing carbon atoms
What do you carbon atoms bond together to form
Different groups called homologous series
What do the Homologous series groups contain
Similar compounds for example alkanes and alkenes are both examples of different homologous series
What is crude oil formed from
The remains of plankton as well as other animals and plants that died millions of years ago
What is plankton
Plankton or tiny living plants and animals which float around in the ocean and waters
What is an alkane
A saturated hydrocarbon for example methane Ethane and propane
What is an alkene
An unsaturated hydrocarbon which contains a carbon-carbon double bond for example ethene
How can you tell if a molecule is an alkane or alkene
If it is an alkane they will only have a single carbon bond but if it is an alkene they will have a double carbon bond
What is fractional distillation
When different compounds in crude oil or separated
How does fractional distillation work
Oil is heated until most of it has evaporated, the gases then enter a fractionating column, in the column it’s hot at the bottom and get a cooler as you go up
Why do shorter hydrocarbons have low boiling points
Because they are still gases at low temperature so they don’t condense and turn back into liquid until they move up the top of the column
Why do longer hydrocarbons have higher boiling points
Because they’ll only stay gas if very hot so as they move up the column it gets cooler so they can condense back into liquids and drain out of the column earlier when they’re near the bottom
What is cracking
Cracking means to split up long chain hydrocarbons
What is the process called when longer alkane molecules are into smaller more useful ones
Cracking
Cracking is a thermal decomposition reaction what does this mean
This means the molecules are broken down by heating them, this can be done by catalytic cracking or by steam cracking
Why is there a high demand for fuels with small molecules
Because short chain hydrocarbons tend to be more useful than a long chain hydrocarbons
How does steam cracking happen
Long chain hydrocarbons are heated to turn them into a gas, the hydrocarbon vapour is mixed with steam, they are then heated to a very high temperature which split them into smaller molecules
How does catalytic cracking happen
Long chain hydrocarbons are heated to turn them into gas then the vapours Passover hot powdered aluminium oxide catalyst, the long chain molecule split apart on the surface of the specs of catalyst
What does complete combustion occur
When there is plenty of oxygen
What is the chemical formula for complete combustion
Hydrogen + oxygen = Co2 + water + energy
What is combustion
A chemical process or reaction between hydrocarbons and oxygen
What happens during combustion
During combustion both carbon and hydrogen form the hydrocarbon are oxidised, oxidation is the gain of oxygen
What is the word equation for the complete combustion of an alkane
Alkane + oxygen = Co2 + water
How can you tell if hydrocarbons are alkanes
You times it by two and add two
What for substances that are fuel made from crude oil
Diesel oil, petrol, liquefied petroleum gas (LPG) kerosene
Name two types of hydrocarbons are produced as a result of cracking
Alkanes, Alkenes
State one way on how catalytic cracking is different from steam cracking
The vapour is mixed in steam cracking, but in catalytic it is passed
What states happen to the evaporated crude oil within the fractionating column
It turns into a gas, the gas is another fractionating column and the liquid is drained off
In fractional distillation of crude oil the hydrocarbons are separated out depending on the length of the carbon chain how does this happen
Longer chain hydrocarbons have high boiling points and will only stay if a gas is very hot, The shorter hydrocarbons have lower boiling points, this means that they are still gases at low temperatures so they do not condense and turn back into liquids
