3.1.5 Kinetics

Question 1

Define rate of reaction

Answer 1

Change in concentration over time

Question 2

Define activation energy

Answer 2

The minimum energy required to start a reaction

Question 3

What increases the frequency of particle collisions?

Answer 3

• Larger SA
• Higher concentration
• Higher pressure
• Higher temeperature
• Catalyst

Question 4

What increases the energy of collisions?

Answer 4

Higher temperature

Question 5

How does a catalyst work?

Answer 5

Lowers the activation energy required to start a reaction by providing an alternative reaction pathway

Question 6

In what ways could you measure rate of reaction?

Answer 6

• Volume of gas produced over time
• Change in mass of reactants over time
• Colour change over time

Question 7

How would increasing the pressure of a gaseous reaction impact the rate of reaction?

Answer 7

Increased rate of reaction
- More particles in the same space
- Increased frequency of successful collisions

Question 8

What are the axis to the Maxwell-Boltzmann distribution curve?

Answer 8

x = energy
y = number of molecules

Question 9

What are the axis to the Maxwell-Boltzmann distribution curve?

Answer 9

x = energy
y = number of molecules

Question 10

What does the area under the Maxwell-Boltzmann distribution curve represent?

Answer 10

Total number of molecules

Question 11

What does the energy at the highest point of the Maxwell-Boltzmann distribution curve represent?

Answer 11

The most probable energy

Question 12

Explain how a small increase in temperature can have large impact on the rate of reaction.

Answer 12

• Much higher proportion of molecules will have the activation energy or higher
• Many more successful collisions per second between the molecules so rate of reaction increases by a large amount

Question 13

Explain the process that causes some molecules in a sample to have a very low energy.

Answer 13

Collisions with other molecules will cause the molecules to lose energy

Question 14

Explain why even in a fast reaction, a very small % of collisions are successful?

Answer 14

Only a small proportion of molecules have the activation energy or higher

Question 15

With reference to the Maxwell-Boltzmann distribution, how does a catalyst increase the number of successful collisions?

Answer 15

• Catalyst lowers the activation energy for a reaction by finding an alternative reaction pathway
• A higher proportion of molecules have the activation energy or higher
• Increased frequency of successful collisions