Chemistry QWC's

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  • Created by: Katy **
  • Created on: 20-05-13 17:45

The extraction of Aluminium from its ore

Aluminium is found in the Earth's crust as Aluminium ore (impure Aluminium oxide.) Aluminium can't be removed from its ore like Iron as it is a more reactive metal, so electrolysis is used (the breaking apart of a compound using electricity.) For electrolysis to work Aluminium has to be motlen for the ions (Al3+ & O2-) to be free to move.

At the negative electrode, the aluminium ion will gain 3 electrons to form an aluminium atom

  • Al3+ + 3e- → Al

At the positive electrode, the oxygen will loose 4 electrons to form oxygen atoms

  • 2O2- - 4e- → 02

Opposite sides attract

The overall reaction taking place is

  • Aluminium oxide → Aluminium + Oxygen
  • 2Al203 → 4Al + 302

Cryolite (compound)  is added to Aluminium oxide to lower the melting point (less electricity.)

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The extraction of Iron from its ore

Iron ore is found in the Earth's crust & Iron is removed from its ore in a blast furnace. The raw materials put into a blast furnace are

  • Iron(3)oxide - source of the Iron
  • Carbon (Coke) - fuel to heat the furnace
  • Hot Air - help the coke to burn
  • Limestone - removes impurities

The carbon reacts with hot air to make carbon monoxide, which will react with Iron ore

  • Fe2O3 + 3CO → 2Fe + 3CO2

Iron(3)oxide = reduced

Carbon monoxide = oxidised

This reaction coninuously happens in a blast furnace with new raw materials being added and the molten Iron being removed.

The limestone reacts with impurities to make ****.

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How do you make Copper sulfate crystals?

  • Heat the Sulferic acid


  • Add the Copper oxide in excess & stir until no more has reacted - you will know all the Copper had reacted as the unreacted Copper will be a black solid at the bottem of the beaker, the solution will be blue and the fizzing due to the carbon dioxide will stop.


  • Next filter the Copper sulfate solution to remove all unreacted Copper oxide.


  • Heat the Copper sulfate solution to evaporate 1/3 of the water.


  • Finally leave the hot saturated solution to cool and crystals of Copper sulfate will appear.
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Crude Oil

Crude oil is made out of simple marine organisms over millions of years. It is made up of different lengthed hydrocarbons (hydrogen & carbon atoms). Crude oil can be used to make fuels or plastics.

To make fuels; the hyrdocarbons are split fractions via fractional distillation. Fractions of hydrocarbons of similar length and this can into happen as the fractions are a mixture of hydrocarbons with different boiling points.

The fractions can then be cracked, which is the breaking apart of long chain hyrdocarbons at high temperature to make monomers.

Monomers then undergo a reaction called additional polymerisation to make polymers, which can be used to make plastics.

Plastics are not disposed properly as plastics aren't biodegradable & they release toxic fumes  & carbon dioxide gas when burnt.

Plastics should be recycled as the crude oil only has a limited amount of supply left (running out,) the landfill sites are becoming full and recycling plastics uses less energy than making new plastics.

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Describe 'Global Warming'

Global Warming is the effect of the Earth's temperature increasing.

It is due to an increase in the amount of carbon dioxide emitted into the atmostphere and creates a layer of gas (the greenhouse gases) and stops the sun's ray from escaping.

The amount of carbon dioxide produced is due to the increasing burning of fossil fuels. An increase in carbon dioxide will cause severe weather conditions, faster melting ice-caps,the sea levels rising and and increase in floods and droughts.

We can slow down this process by reducing the amount of carbon dioxide we produce, for example we can use less fossil fuels and cut down on deforestation. Also industries use 'carbon capture' to reduce ther amount of carbon dioxide released into the atmophere. The carbon dioxide is stored in old oil/gas field rather than being released ito the air.

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Exlpain the Carbon Cycle

Everything with life on this planet is carbon-based & there is a fixed supply on this planet.

For life to survive, it is essential that this carbon is recycled. This is done by the carbon cycle.

The carbon (dioxide) in the atmsphere is extracted and converted into glucose for the green plants in a process called photosynethesis. The plants can then respire the carbon dioxide back into the air or be fed on by animals and the carbon transferred to the animals. Also the animals can respire the carbon dioxide into the air.

Both the animals & plants will die which will provides materials for micro-organisms to feed on, & they resprie carbon dioxide back into the air.

Finally the combustion of fossil fuels will lead to an increase in carbon dioxide which can lead to global warming.

Industries use 'carbon capture' to reduce the amount of carbon dioxide being released. The carbon dioxide is stored in old oil/gas fields rather than being released back into the atmosphere.

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Periodic table through the ages

The elements were first arranged by a man called Mendeleev. He arranged the elements in their atomic mass number & with their similar properties, if elements didn't fit the pattern he left gaps for elements which he predicted would be found in the future.

Now the elements are arranged in atomic number & the gaps have been filled, also the elements are still in simialar properties.

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What are Nano-particles?

A nano-particle is a particle 1-100 nanometres.

When particles are reduced to the nanoscale their properties change -

  • nanosized silver are anti bacterial/fungal/viral  :  sterilising spray, coating insides of fridges
  • nanosized titanium dioxide repels water  :  self cleaning windows
  • nanosized zinc oxide is transparent  :  clear suncream

Nano-particles are used in cosmetics but the particles could be absorbed into the blood stream through the skin & humans could be affected by them.

We don't know the long term effects of nano-particles on humans & the environment.

In the short term they appear safe.

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