Crude oil Flashcards
What are the main fractions obtained from crude oil?
The main fractions obtained from crude oil are liquified petroleum gas, petrol, kerosene, diesel, fuel oil and bitumen.
What is the use of liquified petroleum gas (LPG) obtained from crude oil?
LPG is used for domestic heating and cooking.
What is the use of petrol (gasoline) obtained from crude oil?
Petrol is used as fuel for cars.
What is the use of kerosene obtained from crude oil?
Kerosene is used as jet fuel (paraffin).
What is the use of diesel obtained from crude oil?
Diesel is used for diesel engines (gas oil).
What is the use of heavy fuel oil obtained from crude oil?
Heavy fuel oil is used for ships and power stations
What is the use of bitumen obtained from crude oil?
Bitumen is used for surfacing roads
What is a fuel?
A fuel is a substance that, when burned, releases heat energy.
What are the products of complete combustion of hydrocarbons?
carbon dioxide and water.
What are the products of incomplete combustion of hydrocarbons?
carbon monoxide, soot, and water.
Why is carbon monoxide poisonous?
reduces the capacity of blood to carry oxygen.
What happens in car engines that leads to the formation of nitrogen oxides?
High temperatures in car engines allow nitrogen and oxygen from the air to react, forming nitrogen oxides.
How does the combustion of impurities in hydrocarbon fuels lead to the formation of sulfur dioxide?
When fossil fuels are burned, sulfur impurities are oxidized to produce sulfur dioxide.
How do sulfur dioxide and oxides of nitrogen contribute to acid rain?
Sulfur dioxide and oxides of nitrogen can react with water in the atmosphere to produce acid rain.
How are long-chained alkanes as well as short-chained alkanes converted to alkenes?
Long-chain alkanes are converted by catalytic cracking at a high temperature using silica or alumina as the catalyst.
Why is cracking necessary?
it allows for the production of smaller, more useful products from larger, less valuable ones
Describe how compound D can be obtained from crude oil using the industrial process of fractional distillation. (4)
- The crude oil is heated and vaporized
- Vapour enters into the bottom part of the fractionating column
- There is a temperature gradient in the column
- Different hydrocarbons have different boiling points and compound D can be collected from the top part of the column as refinery gas.
Describe how the boiling point, colour, and viscosity of the fuel oil fraction differ from those of the gasoline fraction
Fuel oil fraction has a higher boiling point, darker color, and higher viscosity.
State the condition that causes incomplete combustion
lack of air
Explain why cracking is an important process in the oil industry
- Produces smaller molecules
- Smaller molecules have greater demand
- Smaller molecules are used to make petrol
- Cracking produces alkenes which are to make plastics
Explain why it is important to crack long-chain hydrocarbon fractions.
- Smaller molecules are in greater demand
- Greater supply of long-chain hydrocarbons
The petrol fraction is obtained from near the top of the column.
The bitumen fraction is obtained from the bottom of the column.
Explain how the petrol and bitumen fractions differ in their properties and uses. (6)
- petrol has shorter (carbon) chains
- petrol has a lower melting point/boiling point
- petrol has a lower viscosity
- petrol ignites/burns more easily
- bitumen does not combust completely (due to the high number of carbon atoms per molecule)
- burning bitumen produces lots of carbon monoxide/soot
Uses of petrol fraction:
- fuels in cars/motorbikes/transport
Uses of bitumen fraction:
- used for road surfaces
