8: Reaction Kinetics

Question 1

Activation energy

Answer 1

The minimum amount of energy for particles to collide with for a successful reaction to take place

Question 2

Collision theory

Answer 2

​Reactions can only occur when collisions take place between particles that collide with sufficient energy and the correct orientation

Question 3

Effect of concentration on reaction rate [2]

Answer 3

-​As the concentration of reactants increases, the
reacting particles get closer together meaning they will collide more often
- As a result, there will be a higher rate of successful collisions and a faster rate of reaction

Question 4

Effect of pressure on reaction rate [2]

Answer 4

• ​As the pressure of gaseous reactants increases, the
  reacting particles get closer together meaning they will collide more often.
  -As a result, there will
  be a higher rate of successful collisions and a faster rate of reaction

Question 5

Effect of temperature on reaction rate [3]

Answer 5

​-Increasing the temperature means the particles will
have more kinetic energy and so will move faster.
-If the molecules are moving faster they will collide more often and, since they’ve gained kinetic energy, a larger proportion of the particles
will have at least the activation energy.
-For both these reasons the rate of reaction increases.

Question 6

Energy profile

Answer 6

​A graph used to show the relative energy levels of reaction species (including reactants and products) as a reaction proceeds

Question 7

Maxwell-Boltzmann distribution [2]

Answer 7

-Shows the distribution of the molecular energies in a gas at a
constant temperature.
-The area under the curve indicates the total number of particles present

Question 8

Rate of reaction [2]

Answer 8

The measure of the amount of product formed or reactant used over time.
-The units of rate of reaction may be given as g/s, cm​3​/s or mol/s

Question 9

Successful collisions

Answer 9

Collisions that occur with sufficient energy for a reaction to occur