Rate of reaction - useful notes.

Rate of reaction.

Helpful notes on 'rates of reaction'. 

Factors affecting it: Temperature;Catalysts;Concentration;Surface Area..

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  • Created by: Emily
  • Created on: 27-11-11 00:22

Rates of Reaction

Rates of reaction

Affected by: 




Surface Area.

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The Effect of Surface Area

Substances react by colliding with enough energy. 

  • Large surface area - more collisions. 
  • More collions = higher proportion of successful collisions, so the higher the rate of reaction.
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The Effect of Temperature.

Increasing temperature: 

  • Particles have more kinetic energy.
  • Particles move around faster.
  • Collision occur more frequently and will be harder. Therfore more successful, increasing the rate of reaction. 

The higher the temperature, the faster the rate of reaction.

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The Effect of Concentration

Increasing concentration:

  • More particles in a volume (cm3) 
  • Therefore, more collisions per second;
  • The more collisions, the higher proportion of successful collisions; 
  • So, rate of reaction increases.

Low concentration = few collisions 

High concentration = more collisions

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The Effect of Catalysts

A catalyst speeds up the rate of a chemical reaction, without being used up it's self. 

  • Catalysts make chemical processes energy efficient - they can be re-used and so save the energy that would used to create high temperatures.

How do they work?

  • Catalysts aDsorb (attatches) the reactants onto their surface, therefore making them more likely to react. 
  • For collisions to be successful, they must occur with enough energy. This is known as the ACTIVATION ENERGY
  • Catalysts work by lowering the activation energy.
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Measuring Rates of Reaction.

There are two ways to measure 'Rates of Reactions': 

  • Measure the rate at which a reactant is used up.
  • Measure the rate at which a product is formed.

Things to measure:

  • The mass of a substance.
  • The volume of a gas is usually measured with a gas syringe, or sometimes an upside-down measuring cylinder or burette.

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Very helpful notes for my Unit 2, Chemistry exam! Thanks Emily!:D 

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