Topic 5: Crude Oil, Fuels and Organic Chemistry Flashcards
A* (55 cards)
What is organic chemistry?
The chemistry of carbon-bases compounds.
What is crude oil?
A mixture of hydrocarbons formed from the remains of marine organisms over millions of years.
What are hydrocarbons?
Organic compounds containing only hydrogen and carbon.
What is fractional distillation?
A way of separating out different ‘fractions’ of the crude oil.
What is a fraction?
A component of crude oil, with its own particular molecular composition, weight and boiling point.
What are the 4 steps of fractional distillation? (summarised)
- Oil heated, gaseous mixture created.
- Put into fractional distillation column = very high temperatures.
- Extraction and condensing of gases/liquids.
What are the 4 properties of hydrocarbons at the top of the column?
Small molecules
Low B.P
Ignite easily
Less dense
What are the properties of hydrocarbons at the bottom of the column?
Large molecules
High B.P
Do not ignite easily
Viscous
What are 2 economic and political factors of crude oil?
Price of crude oil controlled by oil companies, which influences the economy
War in an oil-producing country restricts crude oil supplies (like Russia right now)
What are 4 social and environmental factors of crude oil?
Poorer countries deprived of oil - electricity and heat
Lots of jobs provided
Lots of CO₂ produced
oil spillages may kill habitats
What is cracking?
The breaking down of covalent bonds in large chain hydrocarbons to produce shorter chains.
What are 2 reasons why is cracking used?
Smaller chains have better properties as they are better fuels.
They can also produce monomers for plastic.
What are the conditions of cracking?
600-700°C
Catalyst - silica/aluminia
What is a fuel?
A combustable substance that reaction with oxygen (in the air) to release useful energy (exothermic).
What is the equation for complete combustion?
hydrocarbon + oxygen -> carbon dioxide + water
(eg) CH₄ + 2O₂ -> CO₂ + H₂O
What happens in incomplete combustion?
Carbon monoxide is produced as well.
It is poisonous and produces acid rain so we don’t want this.
What is the equation for measuring the energy released by fuel?
Energy transferred (J) = mass of water heated (g) x 4.2 x temperature rise (°C)
What is the benefit of hydrogen fuel?
Only produces water when burned:
2H₂ + O₂ -> 2H₂O
What are 3 disadvantages to hydrogen fuel?
Must be reacted with coal/neutral gas = not carbon neutral
Hydrogen = flammable
Must be stored in chilled + compressed conditions
What is the fire triangle?
The factors required to make fire: oxygen, heat, fuel.
How is oxygen removed from a fire?
Smothering the fire/ replacing O with CO₂
How is heat removed from a fire?
Water - not on oil/electric fires though
How is fuel removed from a fire?
Getting rid of it (like cutting down trees in a forest fire).
Or have material coated in non-flammable materials (like certain types of chemicals in clothes).
What is the 4 step method to calorimetry?
- Cold water measured into copper calorimeter (small metal can)
- Starting temperature of water recorded
- Water heated using Bunsen burner
- Final temperature of water recorded.
