rates of reaction

• collision theory 


  for a successful collision molecules have to collide with sufficient energy and must collide in correct orientation
• activation energy 


  minimum amount of energy to start a reaction
• concentration of solution 


  higher the concentration the faster the reaction

  particles are now closer together so more frequent successful collisions
• surface area of a solid

  the more surface area the faster the rate of reaction

  more particles are exposed for particles to collide leading to more successful collisions
• pressure of gases 


  the more pressure the faster the rate of reaction

  less space for molecules to move around cause them to collide leading to more successful collisions
• temperature


  the higher the temperature the faster the rate of reaction

  temperature increases the movement of particles due to more kinetic energy cause particles to collide more leading to more successful collisions
• catalyst 


  if there is a catalyst the rate of reaction is faster

  this is because it lowers the activation energy and provides a alternative pathway leading to particles to collide more
• catalyst

  substance that speeds up reaction without being used up by lowering activation energy by providing an alternative pathway
• desorbed means leaving the substance
• absorbed means through the whole substance
• adsorbed means only on the surface
• catalysts: how do they work?


  substance is adsorbed on surface of catalyst near active site

  weakening bonds/more favourable orientation

  reaction taking place

  products are desorbed
• homogenous

  reactants and catalyst are in the same state
• heterogenous 


  reactants and catalysts are at different states
• catalytic converters are heterogenous