The Boltzmann Distribution

Question 1

what is the energy of moving particles?

Answer 1

• in a gas, liquid or a solutions:
• some molecules move slowly with low energy
• some molecules move fast with high energy
• most molecules move close to the average speed and have close to average energy

Question 2

what is on the x axis of the boltzmann distribution?

Answer 2

energy

Question 3

what is on the y axis of the boltzmann distribution?

Answer 3

number of molecules with a given energy

Question 4

what does the larger area of Boltzmann distribution show?

Answer 4

most molecules are moving at a moderate speed so their energies are in this range

Question 5

what does the lower area of the Boltzmann distribution show?

Answer 5

the activation energy which is where some molecules have more energy than the activation energy, so those are the only ones that can react

Question 6

what are features of boltzmann distribution?

Answer 6

• no molecules have zero energy, so the curve starts at the origin (0,0)
• area under the curve = total number of molecules
• no maximum energy for a molecule, so the curve does not meet the x-axis

Question 7

how does Boltzmann change with temperature?

Answer 7

• as the temp increases, the average energy of molecules increases
• small proportion of molecules will still have low energy, but more molecules have higher energy
• changes the Boltzmann distribution curve

Question 8

how does the shape of the Boltzmann distribution change with temperature?

Answer 8

the peak is lower and shifted to the right
- the same area under the curve

Question 9

how does boltzmann distribution change at higher temperatures?

Answer 9

• more molecules have energy equal to or greater than activation energy
• greater proportion of collisions with correct orientation and sufficient energy leads to a reaction
• collisions are more frequent increasing the rate of reaction

Question 10

how does the Boltzmann distribution curve change with catalyst?

Answer 10

• catalyst provides an alternative reaction pathway with a lower activation energy
• compared to the activation energy without a catalyst more molecules have energy greater than or equal to the lower activation energy , so more molecules react to form products