Organic Flashcards
What is crude oil?
A mixture of hydrocarbons
What is crude oil formed from?
The remains of ancient biomass (mostly plankton) that was buried in mud
What is a finite resource?
One that will run out
Why is crude oil a finite resource?
Because it takes longer to form than the rate at which we are using it up
What is a hydrocarbon?
A compound made of atoms of carbon and hydrogen only
What is a general formula?
A mathematical formula which allows you to work out the chemical formula of a substance
What is an alkane?
A hydrocarbon with only single bonds
Name the first four alkanes
Methane, ethane, propane, butane
What is the general formula for alkanes?
CnH2n+2 (the n and 2n are small)
How does boiling point change with the length of an alkane?
The longer the alkane, the higher its boiling point
How does viscosity change with the length of an alkane?
The longer the alkane, the more viscous (the thicker) it is
How does flammability change with the length of an alkane?
The longer the alkane, the less flammable it is
What is fractional distillation?
A process used to separate mixtures of substances with different boiling points
What are the steps involved in fractional distillation?
Crude oil is vaporised, different molecules rise up the fractionating column and cool down. Condense at different points on the column.
Why is fractional distillation important?
Because the different fractions have different uses
What is a fuel?
A substance which when reacted with oxygen releases energy
Name five fuels we obtain from crude oil
Petrol, diesel, kerosene, heavy fuel oil and liquefied petroleum gases
What other uses are there for products of fractional distillation?
Solvents, lubricants, polymers and detergents
What is combustion?
The reaction of a fuel with oxygen
What are the products of complete combustion?
Carbon dioxide and water
When does incomplete combustion occur?
When there is not enough oxygen present
What is cracking?
The process of breaking down a long hydrocarbon into smaller hydrocarbons
What are the products of cracking?
Short alkanes and alkenes
Why is cracking important?
Because smaller hydrocarbons are more useful than longer ones
What are the two types of cracking?
Catalytic and steam cracking
What are alkenes
A different type of hydrocarbon which is more reactive than an alkane
What are alkenes used for?
As a starting material to make more useful chemicals
How do you test for an alkene?
React it with bromine water
What is the colour change when an alkene reacts with bromine water?
Turns from orange to colourless
What is an alkene?
A hydrocarbon with a double bond
What is the general formula for alkenes?
CnH2n
What does unsaturated means?
Contains double bonds (which could become C-H bonds)
What are the first four alkenes?
Ethene, propene, butene, pentene
What are the four reactions of alkenes?
Combustion, with water, with hydrogen and with halogens
How is the combustion of alkenes different to combustion of alkanes?
Alkenes usually react by incomplete combustion so burn with smoky flames
Why are the reactions of alkenes with hydrogen, water and halogens known as “addition” reactions?
Because new atoms are being added to the molecule by breaking the double bond
What is the product from the reaction of an alkene with hydrogen?
An alkane
What conditions are necessary in the reaction of alkenes with hydrogen?
60°C, Nickel catalyst
What is the product from the reaction of an alkene with a halogen?
An alkane with two halogen atoms where the double bond used to be
What is the product from the reaction of an alkene with steam?
An alcohol
What conditions are necessary for the reaction of alkenes with steam?
High temperature, high pressure, catalyst
What functional group do all alcohols have?
OH
Name and draw the first four alcohols
Methanol, ethanol, propanol, butanol (ethanol pictured)
What happens when an alcohol reacts with sodium?
It forms a sodium salt (e.g. sodium ethoxide from ethanol) and releases hydrogen gas.
What are the products of a combustion reaction involving an alcohol and oxygen?
Carbon dioxide and water
Write a symbol equation for the reaction of methanol/ethanol/propanol/butanol with oxygen
E.g CH₃CH₂OH + 5O₂ → 2CO₂ + 3H₂O
Do alcohols dissolve in water?
Yes, they form neutral solutions
How do alcohols react with oxidizing agents?
They turn into carboxylic acids
What are the main uses of alcohols?
Solvents, ethanol used as drinking alcohol and a biofuel
What is fermentation?
The process of turning glucose (a natural sugar) into ethanol
What is required for natural fermentation?
Yeast
What functional groups do all carboxylic acids have?
COOH
Name and draw the first four carboxylic acids
Methanoic acid, ethanoic acid, propanoic acid, butanoic acid (image is ethanoic acid)
Why are carboxylic acids weak acids?
Not all their molecules ionise when in water
What is the product of a reaction between an alcohol and a carboxylic acid?
An ester
What is polymerisation?
The process of using small molecules (monomers) to make long chain molecules (polymers)
What are the two types of polymerisation?
Addition and condensation
What monomers are involved in addition polymerisation?
Alkenes
How do we draw polymers?
In round brackets with an n [poly(ethene) is shown]
What type of monomers are involved in condensation polymerisation?
Ones with two functional groups (like a diol)
What are the products of condensation polymerization?
A polymer and a small molecule (usually water)
What is an amino acid?
A biological molecule with two functional groups
Which functional groups do amino acids have?
NH₂ and -COOH
What do amino acids form during a condensation reaction?
Polypeptides
What is formed from different amino acids combined in one chain?
Proteins
What does DNA stand for?
Deoxyribonucleic acid
What is DNA?
A large molecule containing genetic information
What is the structure of DNA?
Two polymer chains made from nucleotides in the form of a double helix
Name four naturally occurring polymers
DNA, proteins, starch, cellulose
What monomers are starch and cellulose made of?
Glucose
