C9- Crude Oils And Fuels Flashcards
What is Crude Oil?
1) Crude Oil is a finite resource found in rocks. It is a mixture of a large number of compounds. Mostly made up of hydrocarbons.
What are hydrocarbons? What are most of the hydrocarbons found in crude all called?
1) Hydrocarbons are molecules made up mostly of hydrogen and carbon atoms only.
2) Alkanes are most of the hydrocarbons in crude oil.
What are the first four memebsr of the alkanes?
How can alkane molecules be reprsented?
1) Methane
2) Ethane
3) Propane
4) Butane.
Most alkane molecules can be represnted by: C2H6
Explain what Fractional Distillation is.
1) Fractional Distillation is the process used to separate hydrocarbons with similar boiling points called fractions.
Expain the process of Fractional Distillation
1) Crude Oil is heated and fed in near the bottom of the fractionating column as hot vapour. The column is kept very hot at the bottom and is much cooler at the top.
2) Gases move up the column and the hydrocarbons condense when they reach the temperature of their boiling points. Hydrocarbons with the higher boiling points will start to evaporate. The column is cololer towards the top and so they will get part of the way up and then condense going down the flask.
3) Once the first liquid has been collected, raise the temperature until the next one reaches the top.
What are some of the properties of hydrocarbons and what do they depend on?
1) Some properties of hydrocarbons depend on the size of their molecules, including:
- Boiling point
- Viscosity
- Flammablity
Explain what Viscosity, Volatility, Flammability and Boiling Point is.
1) Viscosity - how easily it flows
2) Volatility- the tendancy to turn into a gas
3) Flammabilty- how easily it burns
4) Boiling point- the temperature at which the liquid boils or the gas condenses.
Explain what happens during the combustion of hydrocarbon fuels.
1) Energy is released.
2) The carbon and hydrogen in the fuels are oxidised.
3) Products are Carbon Dioxide and Water.
Explain what cracking is. Wha are some methods for cracking?
1) Cracking is the process of breaking down larger/less useful molcules into smaller and more useful ones.
2) Cracking can be done by various methods including catalytic cracking and steam cracking.
What are the conditions used for catalytic cracking and steam cracking?
1) Catalytic cracking uses a temperature of approx 550Cand a catalyst known s zeolite which contains aluminium oxide and silicon oxide.
2) Steam cracking uses a higher temp of over 800C and no catalyst.
Describe the colour change when bromine water reacts with an alkene.
1) The alkenes react with orange bromine water turning it colourless
