Kinetics- chem

• Rates: Changes in a chemical reaction with regards to time
• Factors affecting rate of reaction:

  1. size of particles
  2. Concentration of reagent
  3. Temperature of reagent
  4. Presence of catalyst
  5. Pressure (only for gaseous reactants)
• Reactions take place only if there are collisions between reactant particles
• Successful/ effective collisions:

  Reactant particles effectively form products
• Temperature:

  • At a higher temperature
  • Particles gain heat energy
  • They move faster
  • More collisions
  • More effective collisions
  • Faster rate of reaction
• Concentration:

  • At a higher concentration
  • There are more particles per unit volume
  • More collisions
  • More effective collisions
  • Faster rate of reaction
• Surface area:

  • With a larger surface area
  • Smaller particle size
  • More reactant particles exposed
  • More collisions
  • More effective collisions
  • Faster rate of reaction
• Pressure:

  • At a higher pressure
  • Reacting volume decreases
  • Particles are closer together
  • More collisions
  • More effective collisions
  • Faster rate of reaction
• Catalyst;

  • Speeds up the rate of a chemical reaction
  • Remains chemically unchanged
  • Reactant specific
• Activation energy (Ea);

  • Energy needed to start a chemical reaction
  • Catalyst reduces the minimum activation energy needed for reactions
• Catalyst:

  • Presence of catalyst
  • Reduces the activation energy needed for reaction
  • More reactant particles have the new minimum activation energy to react
  • Provides an alternate reaction path
  • More collisions
  • More effective collisions
  • Faster rate of reaction