Chemistry C6

  • Created by: abbiedye
  • Created on: 25-07-18 14:59

What reactions go at different rates?

  • The rate = how fast the reactants are changed into particles
  • An example of a slow reaction is the rusting or iron and chemical weathering
  • An example of a moderate speed reaction is the reaction of magnesium and acid
  • An example of a fast reaction is burning and explosions
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Why do particles collide in order to react?

Collision theory

  • The more collisions, the faster the reaction
  • The particles must collide with enough energy for the collision to be successful
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How does temperature effect rate of reaction?

  • As temperature increases, particles move faster
  • They collide more frequently
  • They have more energy
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How do concentration and pressure effect reaction?

  • More particles in the same volume
  • Pressure = same particles in a smaller space
  • Collisions are more frequent
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How does surface area effect reaction?

  • Breaking it into smaller pieces will increase its surface area
  • Same volume = more area to work and therefore more collisions
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How does a catalyst effect reaction?

  • It decreases the activation energy
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What are reversible reactions?

  • Reactions that can pass both ways through the equilibrium
  • As the forward and backward reaction is at the same rate, the system is at equilibrium - 'closed system
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Where can the position of equilibrium be?

  • To the right = products greater than reactants
  • To the left = reactants greater than products
  • These depend on: temperature, pressure, and concentration
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What is Le Chatelier's Principle?

  • The idea that if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract that change
  • It can be used to predict the changes in a system
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How do reversible reactions counteract changes?

  • When the reaction increases, the equilibrium will act in the opposite way to try and decrease it
  • When the reaction decreases, the equilibrium will act in the opposite way to try and increase it
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