C123 Flashcards
Describe the makeup of the atmosphere.
Nitrogen 78%, Oxygen 21%, Argon 1%
The evolution of the atmosphere. Discuss.
Volcanoes gave out CO2, water vapour, nitrogen.
Green plants evolved and produced oxygen.
Complex organisms evolved.
Describe fossil fuels and how they burn.
Fossil fuels are normally hydrocarbons, except for coal which is mainly carbon.
They burn to form carbon dioxide and water.
Describe the different forms of carbon pollution.
Carbon dioxide is released during combustion. It is removed from the atmosphere naturally by plants. Carbon monoxide is poisonous. Particulate carbon deposits itself as soot.
How does sulphur pollution occur?
When sulphur impurities in coal are burned, they form sulphur dioxide. It causes acid rain.
How does nitrogen pollution occur?
At high temperatures in car engines, nitrogen reacts with oxygen to form nitrogen oxides. They cause acid rain.
How can we reduce pollution?
Use less electricity.
Dissolve sulphur dioxide in seawater, producing CO2, water and dissolved sulphate.
Spray an alkaline slurry on the gases, producing a sulphite.
Catalytic converters convert nitrogen oxides to nitrogen and oxygen.
Cars can be run on electricity or biofuels.
What is the difference between synthetic and natural materials?
Synthetic materials are man-made.
Natural materials occur in nature.
Discuss different chemical properties.
Melting point Strength, tensile or compressive. Stiffness Hardness Density
How do hydrocarbon properties change?
The strong covalent bonds don’t break as temperature increases. The intermolecular forces do (in smaller molecules more than larger ones).
Describe how fractional distillation functions.
The crude oil is heated and the molecules separate out into fractions based on boiling points. It can then be used for fuels, lubricants, and other products.
What is polymerisation?
When many small molecules join into a large molecule. They can be used for many purposes, including plastic milk bottles, plastic bags, window frames, foam and kettles.
How can polymers be modified?
Chain lengths can be increased to make them stiffer. Cross linking agents can be added to make it stronger. Plasticisers can make it easier to shape. They can be made more crystalline and more strong.
Describe natural and synthetic uses of nanotechnology.
Natural ones include seaspray and combustion. Synthetic ones include when they are added to sports equipment and wound dressings.
How do rocks contain clues to the Earths history?
Magnetic clues can show the movement of tectonic plates. Sedimentary rocks show fossils, waterborne grains or airblown grains.
