Kinetics

• The rate of reaction is the change in concentration of a substance in a given time
• A catalyst is a substance that increases the rate of reaction without being used up by lowering the activation energy by providing an alternative reaction pathway
• The collision theory is the theory that for a chemical reaction to occur the particles must collide with sufficient energy and in the correct orientation
• Collisions must be greater or equal to the activation energy
• increasing concentration increases rate of reaction as

  • Increasing the concentration increases the number of particles in a given volume
  • There are more frequent successful collisions
  • This increases the rate of reaction
• Increasing surface area increases rate of reaction as:

  • More particles are exposed to the other reactants
  • This increases the number of frequent successful collisions
  • This increases the rate of reaction
• Increasing pressure increases rate of reaction as:

  • There is the same number of particles In a smaller volume
  • There is a greater chance of the particles colliding
  • More frequent successful collisions
  • Increases the rate of reaction
• Increasing temperature increase the rate of reaction as:

  • The reactant particles have more kinetic energy (move faster)
  • More particles have E>Ea
  • So there are more frequent successful collisions
  • Increased rate of reaction
• Catalyst increases the rate of reaction as:

  • A catalyst lowers the activation energy by providing an alternate reaction pathway
  • There are more particles which have E>Ea
  • There are more frequent successful collisions
  • Increasing the rate of reaction
• Heterogenous catalyst action is where the catalyst and reactants are in different states
• Homogenous catalyst action is where catalyst and reactants are in the same state
• To measure the rate of reaction:

  • Change in mass
  • Change in gas volume
  • Colour change
• To increase the rate of reaction:

  • More frequent collisions - increase particle speed or have more particles present
  • More successful collisions - give more energy to particles, lower the activation energy
• Maxwell- Boltzmann distribution features:

  • No particles have zero energy
  • no maximum amount of energy
  • Area under the curve is the total number of particles
  • Highest point of the graph is the most probable energy
  • Activation energy is high than the average energy
• How to measure change in mass:

  • record the time
  • carbon dioxide is made which escapes the reaction mixture
  • this will change the mass on the balance
  • as the reaction proceeds the concentration of the acid decreases
  • the rate at which the mss I lost will be proportional to the concentration of the acid
  • as the reaction proceed the rate will decrease
• How to measure gas volumes:

  • record the time
  • carbon dioxide is made which escapes the reaction mixture
  • This is collected in a gas syringe
  • as the reaction proceeds the concentration of the acid decreases
  • the rate at which the gas is collected will be proportional to the confrontation of the acid
  • as the reaction proceeds the rate will therefore decrease
• How the measure the rate of reaction in precipitates:

  • Time how long it takes for a precipitate to form and cover the x