C8: Fuels And Earth Science Flashcards
What are hydrocarbons?
Compounds that contain hydrogen and carbon atoms only
What is crude oil?
- mixture of hydrocarbons
- contains molecules with rings or chains of carbon atoms
- finite resource
Where can crude oil be found?
Under the sea and ground
How can crude oil be separated?
Fractional distillation
How does the process of fractional distillation work to separate crude oil?
- vaporised before it enters a fractionating column
- f.c is hotter at the bottom than the top
- vapours rise up and condense at different fractions depending on their boiling points
- hydrocarbons with low boiling points will be tapped off the top of the column and hydrocarbons with high boiling points will be tapped off at the bottom of the column
Why is crude oil separated?
Unseparated crude oil isn’t very useful but the separated products (petroleum) are very useful
Refinery gas is a fraction of crude oil, what are its common uses?
Heating and cooking
What is a common use of kerosene?
Aircraft fuel
Which fraction of crude oil is used for road surfacing and roofs?
Bitumen
What is fuel oil most commonly used for?
Fuel for large ships and in some power stations
Products from crude oil mostly belong to which homologous series?
Alkane homologous series
What are the only products when a hydrocarbon fuel undergoes complete combustion?
Water and carbon dioxide
When does incomplete combustion occurs?
When there is an insufficient supply of oxygen
What are the products of incomplete combustion?
Carbon particulates - soot
Carbon monoxide
Water
What are the problems with carbon monoxide?
- toxic gas
- colourless and odourless and if breathed in can cause death by preventing the red blood cells from carrying oxygen around the body
How is acid rain produced?
- sulfur dioxide
- evaporates into the air
- it reacts with water In the clouds to form sulfuric acid
What problems can acid rain cause?
- corrodes buildings and statues made of limestone
- kills/ damages the vegetation
What problems are associated with oxides of nitrogen?
- pollutants
- produce acid rain with similar effects
- cause respiratory problems
What’s a non-renewable fossil fuel found in natural gas?
Methane
Are petrol, kerosene and diesel renewable fuels?
No they are non-renewable (finite resources)
What is cracking?
Breaking down large hydrocarbons into smaller more useful ones
What does saturated and unsaturated mean?
Saturated - only contains single bonds
Unsaturated - contains some C=C double bonds
What type of reaction is cracking?
Thermal decomposition
Why is cracking necessary?
The demand for shorter chain alkenes and alkanes is much greater than the demand for long chain alkanes
What produced the gases that formed earths early atmosphere?
Volcanic activity
How was earths early atmosphere formed?
- earths surface was molten with no atmosphere
- cooling caused land masses to solidify
- volcanoes formed on the land masses and released gases which formed the early atmosphere
What was the earths early atmosphere thought to contain?
- little or no oxygen
- large amount of carbon dioxide
- water vapour
- small amounts of other gases
How did oceans form?
Condensation of water vapour
How did the amount of oxygen in the early earths atmosphere increase?
Growth of plants used carbon dioxide for photosynthesis and released oxygen, this increased the amount of oxygen and decreased the amount of carbon dioxide in the atmosphere
What are greenhouse gases?
Various gases in the atmosphere (carbon dioxide, methane and water vapour) that absorb the heat radiated from earth
What is the greenhouse effect?
- electromagnetic radiation from the sun passes through the earths atmosphere
- earth absorbs some radiation and warms up
- heat is radiated from the earth as infrared radiation
- some of the infrared radiation is absorbed by greenhouse gases in the atmosphere which warms the atmosphere
How has human activity increased atmospheric carbon dioxide concentration?
- burning fossil fuels for energy releases carbon dioxide
- deforestation reduces the amount of photosynthesis occurring so less carbon dioxide is converted to oxygen
What is the current composition of earths atmosphere?
Nitrogen - 78%
Oxygen- 21%
Carbon - 0.04%
Argon - 0.93%
What are the effects of global warming?
- melting of polar ice caps
- flooding
- forest fires
How has human activity increased the amount of methane in the atmosphere?
- raising livestock such as cows
- decay of organic waste in landfills sites
How can the effects of global warming be mitigated?
- construct flood defences in areas of low lying land
- use of irrigation systems to provide water in drought
- produce alternative crops which are better adapted to the new environment
