How fast? How furious?

Chemistry GCSE

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  • Created by: charlotte
  • Created on: 04-06-11 14:26

Rates of Reaction

can be increased by...

  • increasing the temperature
  • increasing the surface area
  • increasing the concentration

Activation energy- minimum amount of energy required to cause a reaction

CATALYSTS

...increases the rate of a chemical reaction, without being used up in the process. They work by reducing the activation energy needed for a reaction to happen.

They are used in

  • the cracking of hydrocarbons uses broken pottery
  • the manufacture of ammonia uses iron
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Enzymes...

.... Enzymes are biological catalysts. They control the rate of chemicla reactions which occur in living organisms (take place in cells) Without them rates would be so slow that life would not exist. the conditions they work best in are;

  • pH of about 7.3 (saliva)
  • Enzymes in the stomach need to be acidic
  • Enzymes in the human body work best at around 37C

All chemical reactions are reversible. This means that the products will react to give the reactants that we started with.

Equilibrium- when a reversiable reaction occurs in a closed system. ( it occurs when reactions occur at exactly the same rate in both directions.)

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Ammonia...

...is an alkaline gas which is lighter than air and has an unpleasant smell...

it is produced in the production of ammonium nitrate fertiliser, so there is great economic importance attached to getting the maximum amount of ammonia in the shortest time possible.

IT IS MADE BY THE HABER PROCESS!!!!!!

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The Haber Process...

Raw materials are ;

  • nitrogen- fractional distilation
  • hydrogen- natural gas and steam

Conditions;

  • temperature of 450C
  • pressure of 200 atmospheres
  • iron catalyst- increases the rate at which equilibrium is reached

Fertilisers-

Replace nitrogen in the soil, which has been used up by previous crops.

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Balancing Ionic Compounds...

Atoms have no overall charge...as the positive and negative ions balance eachother out. THIS IS CALLED AN ION...

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