The Boltzmann Distribution

Question 1

What does the Boltzmann Distribution show?

Answer 1

• Shows the energy of each molecule.
• The peak of the curve is the most probable (modal) energy.
• The area under the curve is equal to the number of molecules in the sample.
  —> This does not alter with changing conditions.
• Only the molecules with an energy greater than the activation energy, as shown on the graph, are able to undergo a successful collision.

Question 2

How does a changing temperature effect the reaction rate?

Answer 2

• If temperature increases, so does kinetic energy so the number of collisions increases.
• The proportion of molecules with energy > than the activation energy increases.
• The frequency of successful collisions greatly increases.
• Therefore, the rate of reaction greatly increases.

(Inverse for decreasing temp.)

Question 3

How does a change in temperature effect the Boltzmann Distribution?

Answer 3

The curve shifts to the right and the peak drops lower.
—> The area under the curve remains the same as the number of molecules has not changed.

Question 4

What is the effect of a catalyst on the reaction rate?

Answer 4

• The activation energy is reduced , so more molecules successfully collide with an energy which is greater than the activation energy.
• Therefore the rate of reaction increases.