2.5 - Crude oil, fuels and organic chemistry Flashcards
What is crude oil?
A finite resource found in rocks, formed over millions of years from the remains of simple marine organisms
It contains a complex mixture of hydrocarbons
What are the processes in the fractional distillation of crude oil?
Note: Crude oil is evaporated inside a blast furnace before entering
The mixture is put into the fractionating column at the bottom and heated.
The hydrocarbons evaporate and rise up the column.
As the hydrocarbons rise, they eventually reach a fraction which is cool enough for them to condense back into a liquid.
The mixture left at the bottom, which does not evaporate is called bitumen
What are fractions in fractional distilation?
Fractions contain mixtures of hydrocarbons (alkanes) with similar boiling point
As you go up the fractionating column, the hydrocarbons have? Talk about: Chain length Boiling point Volatility Flammability Colour
smaller chain lengths lower boiling points more volatility (easy to evaporate) higher flammability (they ignite more easily and burn more cleanly) lighter colour (the bottom fraction is black, the middle fractions range from brown to yellow and the fraction at the top is colourless)
A tall fractionating column is fitted above the mixture, with several condensers coming off at different heights. The column is ___ (hot/cool) at the bottom and ___ (hot/cool) at the top. Substances with high boiling points condense at the ____ (top/bottom) and substances with lower boiling points condense on the way to the ___ (top/bottom)
Hot
Cool
Bottom
Top
What is the economic importance of the oil industry?
Oil companies set the price of oil so there is an influence globally on the economy - it can be harder for poorer countries to buy oil.
War or internal crisis within a country that produces oil can effect the flow of oil to other countries which they sell to.
What is the political importance of the oil industry?
Countries that are large producers of oil can essentially cut off oil supplies to other countries.
This is used as a political tool
What are the environmental impacts of the oil industry?
Burring fossil fuels releases large amounts of carbon dioxide, a greenhouse gas, into the atmosphere, contributing to global warming and climate change
The building of power stations and the process of drilling for oil causes damage to the landscape and loss of habitat
Oil spillages into the ocean result in the deaths of marine life and birds and are often dealt with setting them alight
What is cracking used for?
Allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules.
In cracking, fractions containing large hydrocarbon molecules are heated to vaporise them. They are then:
heated to _____
passed over a catalyst of ____ or ____
600-700°C
silica, alumina
What are the combustion reactions of hydrocarbons?
When hydrocarbons burn in plenty of oxygen it will combust as follows: hydrocarbon + oxygen → carbon dioxide + water
What is the fire triangle?
A symbol that contains 3 things needed for a fire to burn: oxygen, fuel and heat
Removing any of these will cause the fire to stop burning
What method do you use to remove oxygen, heat and fuel from a fire? What is the type of fire?
Oxygen - Fire blanket, CO2 extinguisher
Oil fires, chip-pan fires, electrical fires
Heat - Water
House fires, wood fires, paper fires
Fuel - Firebreak
Forest fires
What is calorimetry?
An experiment technique used to workout the energy released when burning a fuel
What is the method of Calorimetry?
1) A know volume of water is added to a calorimeter and the temp is recorded
2) A known mass of fuel is burnt beneath the calorimeter
3) The maximum temperature of the water and the final mass of the fuel is recorded
When comparing different fuels, it is important to carry out a fair test. Several variables should be kept constant. They include:
1) the volume of water used
2) the starting temperature of the water
3) the temperature increase
4) the distance of the flame from the calorimeter
What is the combustion reaction of hydrogen and what are its uses?
Hydrogen burns in oxygen and forms water
Hydrogen is used as a fuel in rockets and some cars
What are the advantages of using hydrogen as a fuel?
No greenhouse gases are produced in the combustion of hydrogen
An alternative fuel option as current fuels are running out
What are the disadvantages of using hydrogen as a fuel?
Hydrogen is extremely flammable
Most of hydrogen produced comes from fossil fuels or electrolysis so it still has a negative impact on the environment.
Hard to store and transport - mist be cooled to very low temperatures so it liquefies for storage and transport.
What are the products of hydrocarbon cracking?
Alkanes and unsaturated hydrocarbons called alkenes
Alkenes are monomers that are used to make plastics
What is the general formula of alkanes?
CnH2n+2
What is the general formula of alkenes?
CnH2n