Factors Affecting Rate of Reaction

• Concentration of Reactants


  • Higher conc. -> More particles present per unit volume

  1. Particles closer to one another, increase in frequency of collisions,
  2. Increase in frequency of effective collisions
  3. Increase in rate of reaction
• Pressure on Gaseous Reactants


  • Increase in pressure, smaller volume as distance between particles decreases

  1. As particles closer to one another, increase frequency of collision,
  2. Increase in frequency of effective collision
  3. Increase in rate of reaction
• Particle Size of Solid Reactants


  • Smaller particle size, larger surface area

  1. Increase in surface area of solid reactants, larger surface area
  2. Increase in frequency of collisions
  3. Increase in frequency of effective collisions
  4. Increase in rate of reaction
• Temperature of Reaction Mixture


  1. As temperature increases, reactant particles gain energy and move more vigorously
  2. Increase in frequency of collisions and increase of number of particles that collide with energy greater or equal to activation energy
  3. Increase in frequency of effective collisions
  4. Increase in rate of reaction
• Catalyst


  • Substance that increases rate of chemical reactions by providing an alternate activation reaction pathway of lower activation energy
  • Remains chemically unchanged at end of chemical reaction
  • Link to transition metals
  • Biological catalysts are called enzymes

  1. Activation energy is lowered
  2. Number of reactant particles colliding with energy greater than or equal to activation energy increases
  3. Increased frequency of collisions
  4. Increased frequency of effective collisions
  5. increased rate of reaction