1.04 kinetics

• what is rate of reaction?

  the speed at which a reaction takes place.
• what is collision theory?

  The theory that chemical reactions only occur when particles collide with more than or equal to the activation energy, and approach eachother in a certain orientation.
• what is activation energy?

  the minimum amount of energy needed for a successful collision to take place.
• what happens in an exothermic reaction?

  the products have less energy than the reactants. Heat energy has been released to surroundings. ΔH has a negative value as energy has been lost.
• what happens in endothermic reactions?

  the products have more energy than the reactants. Heat energy has been formed. ΔH has a positive value as energy has been gained.
• what is collision frequency l?

  the number of collisions per unit of time.
• how does an increase in concentration affect rate of reaction?

  increasing concentration (number of moles per unit volume) will increase the frequency of successful collisions and therefore rate of reaction.
• how will an increase of pressure affect rate of reaction?

  by increasing pressure (same number of particles in a smaller area) the frequency of successful collisions will increase and therefore rate of reaction.
• how does increasing temperature affect rate of reaction?

  increasing temperature (thermal energy) gives a higher kinetic energy so particles move faster (experience more collisions) and have more energy meaning successful collisions are more likely increasing rate of reaction.
• What does the Maxwell Boltzmann distribution show?

  The spread of energies that molecules of a gas or liquid have at a particular temperature
• as temperature increases how does the maxwell boltzmann curve change ?

  modal energy becomes higher (further along)there is a wider spread of valuesmore particles possess the activation energy
• what is a catalyst?

  a substance which increases rate of reaction by providing an alternate reaction pathway with a lower activating energy.
• what structure are catalysts usually?

  giant covalent.
• what block of the periodic table are catalysts usually found?

  P and D.
• what are homogenous catalysts?

  Catalysts that are in the same state/phase as the reactants.
• what are heterogenous catalysts?

  catalysts in a different phase/ state from the reactants.
• what are two economical advantages of catalysts?

  lower Ea so less energy is needed. reduced waste so higher atom economy.
• how do catalysts change the maxwell boltzmann curve?

  the Ea is closer to the modal.