Chapter 14

Question 1

How do you calculate the average thermal energy of a particle?

Answer 1

E=kt (approximately)

Question 2

What is activation energy?

Answer 2

The energy needed by to break bonds in a substance before a reaction can take place. Represented by the greek letter, epsilon

Question 3

When do processes take place at a ‘reasonable rate’?

Answer 3

When the ratio E/kT (where E is activation energy) is between 15 and 30

Question 4

How do different particles in a sample have different energies?

Answer 4

When particles collide, there is an exchange of energy between them. One particle will leave the collision with less energy, and one particle will leave with more. If a particle is ‘lucky’ and leaves many collisions more energy than it entered it with, the energy that it has will increase until it is above the activation energy for a reaction.

Question 5

What is the Boltzmann factor?

Answer 5

e^(-E/kT), where E is the activation energy. Gives the ratio of particles with the required energy to react. The boltzmann factor is proportional to the rate of a reaction

Question 6

What does the graph of Boltzmann factor against temperature look like?

Answer 6

S-shaped curve, with an asymptote at boltzmann factor = 1. In between very high temperatures and very low temperatures, the Boltzmann factor changes very quickly, suggesting that small increases in temperature results in a large change in the Boltzmann factor and therefore the rate of reaction