Kinetics

Question 1

Collision theory

Answer 1

For a reaction to occur it is necessary for the reacting species ( atoms or molecules) to collide with one another with sufficient energy

Question 2

Activation energy

Answer 2

The minimum energy needed to start a reaction

Question 3

Describe what happens to the rate of reaction as we increase the temperature

Answer 3

Increasing the temperature, increases the speed of the particles which will result in more collisions

Question 4

Describe what happens to the rate of reaction as we increase the concentration

Answer 4

More particles in a given volume will increase the frequency of fruitful collisions and increase the rate of reaction

Question 5

Describe what happens to the rate of reaction as we increase the pressure

Answer 5

More molecules in a given volume so collision are more likely

Question 6

Describe what happens to the rate of reaction as we increase the surface area

Answer 6

Increasing surface area means more of its particles are available to collide with molecules

Question 7

Describe what is meant by a catalyst

Answer 7

• A substance that can change the rate of a chemical reaction without being chemically changed itself.
• Lowers activation energy by finding an alternative pathway for the reaction

Question 8

Exothermic reactions

Answer 8

Release energy to the surroundings

Question 9

Endothermic reactions

Answer 9

Take in energy from the surroundings

Question 10

Describe what is meant by The Maxwell-Boltzmann distribution

Answer 10

• A graph that expresses the distribution of the energies of particles.
• The area under the graph represents the total number of particles

Question 11

Why do chemists use catalysts to speed up reactions

Answer 11

• Cheaper than using lots of energy to increase temperature or pressure
• Don’t get used up, therefore they can be re-used