What is crude oil?
A non-renewable resource (finite) formed from the fossilised remains of ancient plankton.
What are the characteristics of hydrocarbons with short chains?
Lower boiling points.
Lower viscosity.
More flammable.
What are the characteristics of hydrocarbons with longer chains?
Higher boiling points
Higher viscosity.
Less flammable.
Crude oil is a mixture of different…
…compounds that aren’t chemically combined.
What are hydrocarbons?
Molecules made up of only hydrogen and carbon atoms which differ in size, causing different properties.
Where is crude oil found?
Rocks.
What features of alkanes make them useful fuels?
Burn well and are quite unreactive.
What are alkanes?
They are saturated hydrocarbons where each carbon atoms is bonded to four hydrogen atoms.
What is the general formula of an alkane?
CnH(2n+2)
Why are alkanes called saturated hydrocarbons?
Only contain single bonds with other atoms.
What are the smallest hydrocarbons?
Methane, ethene, propane and butane.
Most compounds in crude oil are ________ and most of these molecules are _____.
Hydrocarbons,
Alkanes.
What is fractional distillation?
The process of separating crude oil (using their different boiling points) into groups of hydrocarbons with similar numbers of carbon atoms. The groups are called ‘fractions’.
Describe the evaporation process of fractional distillation:
Crude oil is heated until it evaporates.
Crude oil vapour is put into a fractionating column at the bottom and rises upwards.
Describe the condensation process of fractional distillation.
The temperature is highest at the bottom of the column.
Long-chain hydrocarbons condense at the bottom and are collected as liquids. Shorter-chain hydrocarbons condense at the top of the column where the temperatures are lower.
What do fractions processed after fractional distillation used for?
Fuels (petrol, diesel).
Petrochemical industry can use these as feedstock for making solvents, detergents, lubricants etc.
Why are there many organic (carbon-containing) compounds?
Because carbon atoms can form families of similar compounds. These groups are called homologous series.
Name an example of a homologous series:
Alkanes are a family of similar compounds.
They all have the same general formula (CnH(2n+2)) and, consequently, they have similar properties.
The equations for the combustion (burning) of hydrocarbons depend on the…
…amount of oxygen that is available.
If alkanes are burned without enough oxygen, what can be created?
Carbon monoxide 2C +O2 –> 2CO
What is carbon dioxide?
A colourless, odourless toxic gas.
The combustion (burning) of hydrocarbons when there is good air supply involve:
Energy release.
The oxidisation of both carbon and hydrogen to produce carbon dioxide and water.
Heavy fractions of crude oil do not make good fuels because;
They do not ignite easily.
Have low volatility.
Have high boiling points.
What is cracking?
The process that breaks down long-chain (large) hydrocarbons into shorter-chain (smaller), more useful molecules.
Cracking is an example of…
…a thermal decomposition reaction.
Cracking can be done by:
Catalytic cracking.
Steam cracking.
What is the process of catalytic cracking?
Vaporised heavy hydrocarbons are passed over a hot catalyst. The products include alkanes and alkenes.
Hexane –> butane + ethene.
What is the process of steam cracking?
Vaporised heavy hydrocarbons are mixed with steam in high temperature environments. The products include alkanes and alkenes.
Decane –> octane + ethene.
What are the uses of alkenes?
Being combined to make polymers and starting materials for chemicals like ethanol.
What is a functional group?
A group of atoms that determine (decide) how an organic compound will react.
The functional group of alkenes is…
…C=C (a carbon-carbon double bond).
Addition reactions are…
…normal for alkane.
What happens in addition reactions for alkenes.
In these reactions, the carbon-carbon double bond opens up and allows new atoms to bond to the carbons.
What can be added to an alkene to make an alcohol?
In the presence of a phosphoric acid catalyst, water, in the form of steam can be added to an alkene to give an alcohol.
Describe hydrogenation:
Alkenes and hydrogen
In the presence of a nickel catalyst, hydrogen can be added to an alkene to give an alkane.
E.g. ethene (C2H4) + hydrogen (H2) → ethane (C2H6).
Describe a method of distinguishing between alkanes and alkenes:
Alkenes, unlike alkanes, will react when shaken with bromine water.
Describe the reaction between alkenes and bromine water (halogen):
Causes the solution to turn from an orange-brown colour to colourless.
ethene + bromine –> dibromoethane (colourless)
How do alkenes react with oxygen?
React in combustion reactions. React in a similar way to other hydrocarbons.
Why do alkene + oxygen reactions produce smoky flames?
Because their combustion is incomplete.
What is the functional group of alcohols?
(-OH) a hydroxyl group.
What is the general formula for the homologous series of alcohols?
CnH2n+1OH
What is the formula for methanol?
CH3OH
What is the formula for ethanol?
CH3CH2OH
What is the formula for propanol?
CH3CH2CH2OH
What is the formula for butanol?
CH3CH2CH2CH2OH
Alcohols + sodium =
Hydrogen.
Alcohols + water =
Dissolve to make neutral solutions.
Alcohols + strong oxidising agents =
A carboxylic acid.
Alcohols + air + heat =
Carbon dioxide + water
What is the equation for the complete combustion of methanol?
2CH3OH(l) + 3O2(g) = 2CO2(g) + 4H2O(l)
What is fermentation?
Fermentation is a common method for producing ethanol. Ethanol is a key component (part) of alcoholic drinks.
Describe the process of fermentation:
Adding yeast to a sugar solution = an aqueous solution of ethanol + carbon dioxide.
What are the ideal conditions for the fermentation of sugar and yeast?
Temp of 37 degrees.
Slightly acidic solution.
Anaerobic.
What is a carboxylic acid?
A carboxylic acid is an organic compound that contains a carboxyl group.
What functional group do carboxylic acids have?
A carboxyl group (-COOH)
What are the properties of carboxylic acids?
Partially ionise in water (they are weak acids).
Functional group (-COOH)
General formula: CnH2n+1COOH.
Name the 4 smallest carboxylic acids and their formulas.
Methanoic acid - HCOOH
Ethanoic acid - CH3COOH
Propanoic acid - CH3CH2COOH
Butanoic acid - CH3CH2CH2COOH
Carboxylic acid + alcohol = (using an acid catalyst)
Ethanoic acid + ethanol = ethyl ethanoate + water.
ester and water
Carboxylic acid + water =
(dissolve to give) Acidic solutions.
Carboxylic + carbonates =
Salt + carbon dioxide + water.
What is addition polymerisation?
Addition polymerisation is the joining of short-chain monomers to produce one long-chain polymer.
What are monomers?
Alkenes are the monomers used in addition polymerisation.
Why are alkenes the monomers used in addition polymerisation?
Because alkenes can open up carbon-carbon double bonds to join together.
What is a polymer is addition polymerisation?
The only product of the reaction (the repeating unit has the exactly same amount of atoms as the monomer.
What is the product when ethene monomers undergo addition polymerisation?
Poly(ethane) (Add the prefix ‘poly’ and put the monomer in brackets changing the double bond into a single bond.)
What is condensation polymerisation?
Condensation polymerisation describes the joining together of monomers with 2 functional groups to produce larger polymers, as well as small molecule by-products (e.g. H2O).
How are the simplest condensation polymers produced?
The simplest condensation polymers are produced from 2 monomers with 2 of the same functional group on each monomer.
Ethanediol + hexanedioic acid →
Terylene + water.
What are amino acids?
Amino acids are organic compounds that have two different functional groups.
What is the functional group of amine groups?
(-NH2)
Amino acids can be combined by condensation polymerisation to give…
Polypeptide + water.
Functional groups of amino acids:
Carboxyl group and an amine group.
How are polypeptides created?
Bonds, called peptide links, form between the amine and carboxyl group of amino acids, producing polypeptides.
How is a protein formed?
When one or more polypeptides become associated, a macromolecule called a protein is formed.
Name some proteins that have an important role in living organisms:
Enzymes.
Haemoglobin.
Antibodies.
What is the role of haemoglobin?
Transports oxygen in the blood.
What is the role of enzymes?
Catalyse biological reactions.
What are the components of DNA made of?
Polymers are made of monomers called nucleotides.
Each nucleotide of DNA contains 1 of the 4 nitrogenous bases:
Adenine.
Thymine.
Cytosine.
Guanine.
What is the shape of DNA?
2 polymer chains arranged in the form of a double helix.
What is the role of DNA?
DNA encodes (produces) the genetic instructions used in development, functioning and reproduction of living organisms and viruses.
Other naturally occurring polymers (excluding DNA) that are important for life are:
Starch and cellulose (sugars are the monomers).
Proteins (amino acids are the monomers).
