Topic 9 Rate of reactions

• What is the rate equation? [1]

  Rate=K[A]m[B]n
• What happens if [A] stays the same? [1]

  The orde of reaction with respect to A is 0
• What happens if the rate is proportional to [A] ? [1]

  The Oder of reaction with respect to A is 1
• What happens if the rate is proportional to [A]2

  The order of reaction with respect to A is 2
• What happens to the rate of a reaction if you increase the temperature? Why? [2]

  The rate of reaction increases because you are increasing the number of collisions between reactant molecules and also the energy of each collision.
• What is a rate determining step? [3]

  In a series of steps, each step can have a different rate. The overall rate is decided by the step with the lowest rate - the rate determining step
• What is the arrhenuis equation? [2]

  k= Ae^ -Ea/RT
• 3 General rules for the arrhenius equation [3]

  1 As the activation energy gets bigger, k gets smaller

  2 A large Ea will mean a slower rate because if a reaction has a high Ea there will not be many reactant particles with enough energy to react

  3 As temperature rises, k increases. Higher temperatures mean reactant particles move around faster and with more energy so they’re more likely to collide
• State the log equation for arrhenius [2]

  lnK = -Ea/RT + lnA