Crude Oil Flashcards
What is crude oil?
Mixture of hydrocarbons
What is fractional distillation used for?
To separate crude oil out into fractions- groups of molecules with similar sizes and therefore similar properties
How is crude oil separated?
- Crude oil is heated, nearly all of the hydrocarbons turn into gases
- The crude oil vapour then passes into the fractionating column
- The temperature in the column decrease as you go up
- The gases rise up the column, different components condense at different heights due to different boiling points
Describe smaller hydrocarbons
Have lower boiling point, so they make it all the way up the column with out condensing
Describe large hydrocarbons
Collected at the bottom of the column because they have high boiling point and so condensed lower down the column
What is the order of the fractions ?
Refinery gases
Gasoline (petrol)
Kerosine
Diesel oil
Fuel oil
Bitumen
What is the use of refinery gases?
Domestic heating and cooking
Use of gasoline (petrol)?
Fuel in cars
Use of kerosine?
Fuel in planes
Use of diesel oil?
Fuel for lorrie’s, buses, trains
Use of bitumen ?
Road surfaces
Which fraction would be the most flammable ?
Refinery gases
What fraction would be the least volatile?
Bitumen
Which fraction would be the darkest colour ?
Bitumen
As the size of the hydrocarbons molecules increases, colour…?
Gets darker
As the size of the hydrocarbons molecules increases viscosity..?
Increases
High viscosity= thick+sticky
As the size of the hydrocarbons molecules increases boiling point…?
Increases
As the size of the hydrocarbons molecules increases volatility..?
Decreases
How easily a liquid evaporates
As the size of the hydrocarbons molecules increases flammability..?
Decreases
What is fuel?
Substance that, when burned , releases heat energy
What are the products of complete combustion?
CO2+ H2O
Carbon dioxide and water
What are the products of incomplete combustion?
H2O+CO or C
Water+ carbon monoxide or carbon
Why is incomplete combustion harmful to humans?
Carbon monoxide
It bonds to the haemoglobin in the red blood cells and prevents oxygen from being transported around the body
Under what conditions does incomplete combustion occur?
Happens when the supply of air or oxygen is poor
How is sulfur dioxide made?
Sulfur is a common impurity found in fossil fuels
When we burn the fuel, the sulfur is also burnt-it reacts with oxygen in the air to form sulfur dioxide
S+O2=SO2
How is sulfuric acid made?
Sulfur dioxide goes up into the atmosphere and reacts with oxygen and water to form sulfur if acid
SO2+2O2+2H2O=2H2SO4
How is nitrogen oxides formed?
The high temperature inside a car engine causes nitrogen and oxygen in the air to react together to form nitrogen oxides
How is nitric acid formed?
The nitrogen oxides go up into the atmosphere and react with oxygen and water to form nitric acid
HNO3
What is acid rain caused by?
Sulfur dioxide or nitrogen oxides that can be produced when a fossil fuel is burnt
When sulphur dioxide and nitrogen oxides are released into the air
What is cracking?
Process used to break long-chain alkanes down into shorter-chain alkanes and alkenes
Important stuff about cracking ?
Fractional distillation produces more long-chain hydrocarbons than can be used
Cracking turns there into short alkanes which are more useful-petrol, fuel
Cracking also produces alkenes, which are used to make polymers
What are the conditions for cracking ?
-catalyst: silicon dioxide (silica) and aluminium oxide (alumina)
-temperature 600-700°C
What is hydrocarbons?
Compound made of hydrogen and carbon only
