COLLISION THEORY AND CATALYST

• Two factors that determine whether a reaction will occur between two particles that are colliding

  • Substances or particles of reactants must physically collide with enough energy
  • Substance or particles must come into contact or collide in the correct orientation (facing the correct way)
• Collision theory


  States that reacting substances must come into contact (collide) with enough activation energy, and in the correct orientation (facing the correct way), so that their electron shells can rearrange to form the products of the reaction
• Activation energy


  Minimum energy required for a reaction to take place
• Energy of the particles is less than the activation energy

  Collision may not be effective and particles could just bounce off each other unchanged
• Temperature


  Refers to the average kinetic energy of the particles in an object

  A rise in temperature of 10 degrees Celsius doubles the reaction rate
• The rate of a chemical reaction increases with increasing temperature


  Collision between atoms and molecules becomes faster resulting in a build up of more energy
• As the temperature increases, collision between atoms and molecules becomes faster
• Concentration


  • The number of particles present in a given volume of solution
  • A measure of how much of the solute (something to be dissolved) is dissolved in a solvent (dissolving medium) to form a homogeneous mixture
• SURFACE AREA

  As you powder a solid, its surface area becomes greater

  Particles colliding

  Faster reaction happens
• Catalyst


  A substance which speeds up a reaction, but is chemically unchanged at its end
• Adding a catalyst


  Provides an alternative route for the reaction with a lower activation energy