Edexcel GCSE Chemistry Notes | Topic 7

  • Reactions occur when particles collide and rates of reaction are increased when the frequency and/or energy of collisions is increased.
  • The factors affecting rate: temperature, concentration, surface area to volume ratio of a solid, pressure (involving gases). These factors all affect frequency or energy of collisions between particles.
  • Rate of reaction = amount of product formed/ time (upward curve plateaus)
  • Rate of reaction = amount of reactant used/ time (downward curve plateaus)
  • Catalyst: speeds up rate of a reaction without affecting the reaction by reducing activation energy.
  • Activaton energy: minimum energy needed to start a reaction successfully.
  • Enzymes are biological catalysts and they are used in the production of alcoholic drinks
  • Salts dissolving in water: , Neutralisation reactions: , Displacement reactions, Precipitation reactions:
  • Exothermic: heat energy is given out
  • Endothermic: heat energy is taken in
  • Energy change = energy to break reactants - energy to form products.
  • Reaction profiles: