10.3 The Boltzmann Distribution

Question 1

Definition of activation energy

Answer 1

The minimum energy required to start a reaction by breaking bonds

Question 2

What is the symbol for activation energy?

Answer 2

Ea

Question 3

Sketch the Boltzmann distribution graph

Answer 3

Question 4

What are the features of the Boltzmann distribution graph?

Answer 4

-No molecules have zero energy - the curve starts at the origin
-The area under the curve is equal to the total number of molecules
-There is no maximum energy for a molecule - the curve forms not meet the x axis at high energy, the curve would need to meter infinite energy to meet the x-axis

Question 5

Sketch the graph for the effect of temperature on the Boltzmann distribution

Answer 5

Question 6

What are the difference in the Boltzmann distribution graph at higher temperatures?

Answer 6

-The peak is lower and shifted to the right
-The area under the curve remains the same as there is the same number of molecules
-A greater proportion of molecules exceeds the activation energy

Question 7

As temperature increases what happens?

Answer 7

-More molecules have an energy greater than or equal to activation energy
-Therefore there us a greater proportion of collusions that will lead to a reaction, increasing the rate of reaction
-Collisions will also be more frequent as the molecules are moving faster

Question 8

Sketch the graph for the effect of a catalyst on the Boltzmann distribution graph

Answer 8

Question 9

How does the catalyst lower the activation energy?

Answer 9

It will provide an alternate pathway with a lower activation energy (Ea). A greater proportion of molecules now have an energy equal than or greater to Ea, so on collision more molecules will react to form products, this increases the rate of reaction