CC16 Fuels 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? Why is crude oil a finite resource?
One that will run out. 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 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
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 oil, kerosene, 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 formed in incomplete combustion
Carbon monoxide
Why is carbon monoxide dangerous
It is toxic, taken up by red blood cells in preference to oxygen.
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 alkenes
A hydrocarbon with a double bond
What are alkenes used for?
As a starting material to make more useful chemicals
What is the general formula for alkenes?
CnH2n
What are the first four alkenes?
Ethene, propene, butene, pentene
What do members of a homologous series have in common?
Same general formula, differ by CH2 for neighbouring compounds in the series, boiling points increase with chain length, have similar chemical properties and reactions.
How is sulphur dioxide produced?
Sulphur impurities in fuels form it when the fuel is burnt
What happens when the sulphur dioxide dissolves in rain water?
Acid rain is formed
How are oxides of nitrogen formed?
When the nitrogen and oxygen in the air react together at the high temperatures created in combustion engines
State three advantages of hydrogen fuel cells over petrol
Do not need to be recharged, no pollutants are produced only H2O, water is a renewable resource
State three disadvantages of hydrogen fuel cells over petrol
Hydrogen is highly flammable, hydrogen is sometimes produced through non-renewable means, hydrogen is difficult to store and transport
What does finite mean?
It wil run out.
How does ease of ignition change with the length of an alkane?
The longer the alkane, the harder it is to ignite.
How are members of a homologous series different from each other?
Their chain length differs by a number of CH2
Where do petrol, kerosene and diesel oil come from?
They are obtained by fractional distillation of crude oil
Where does methane come from?
It is found in natural gas?
Are petrol, kerosene, diesel and methane renewable or non renewable?
non-renewable
