Rates of reactions, factors affecting the rate of reaction

• what is the rate of a reaction ?

  the speed at which reactants are changed into products
• what is one of the slowest reactions ?

  rusting of iron
• example of a fast reaction ?

  explosions and burning
• example of a moderate speed reaction ?

  magnesium reacting with an acid to produce bubbles
• label this graph

  A) steep gradient fast reaction

  B) shallow gradient slow reaction

  C) increasing amount of product

  
• labrl this graph

  A) steep gradient fast reaction

  B) shallow gradient slow reaction

  C) amount of reactant decreasing

  
• what are things particles must have to react ?

  • collide succesfully
  • have enough energy
  • be in the correct orientation
• whats 1 factor affecting the number of collisions of particles ?

  Temperature
• what happens if you increase the temperature of the collisions of particles ?

  you increase the kinetic energy
• what is the activation energy ?

  The minimum energy required for a chemical reaction to occur.
• what are the 4 main factors affecting the rate of reaction ?

  • Temperature
  • concentration
  • surface area
  • catalysts
• as the temperature increases the particles move faster and collide more frequently, higher temperature also increases the energy of the collisions increasing in general the rate of reaction
• as concentration increases, meaning there are more particles of reactant in the same volume , collisions are more likely to occur increasing in general the rate of reaction
• if one reactant is a solid , breaking it into smaller pieces will increase its surface area to volume ratio meaning the particles will have more area to work on so the frequency of collisions will increase this means that the rate of reaction is faster for solids with a larger surface area to volume ratio
• what is a catalyst ?

  A substance that increases the rate of a chemical reaction without being consumed in the process
• catalysts increase the rate of reaction, this is because they work by decreasing the activation energy needed for a reaction to occur, they do this by providing an alternative reaction pathway that has a lower activation energy meaning more of the particles have at least the minimum amount of energy needed for a reaction to occur when the particles collide