1.5 Kinetics Definitions

Question 1

Define Activation Energy

Answer 1

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

Question 2

Define Catalyst

Answer 2

A substance that increases the rate of a reaction without being changed in chemical composition or amount. They work by providing an alternative reaction pathway with a lower activation energy.

Question 3

Define Collision theory

Answer 3

Reactions can only occur when collisions take place between particles having sufficient energy

Question 4

Define the Effect of concentration on reaction rate

Answer 4

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 5

Define the Effect of pressure on reaction rate

Answer 5

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 6

Define the Effect of temperature on reaction rate

Answer 6

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 7

Define Maxwell-Boltzmann distribution

Answer 7

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

Question 8

Define Rate of reaction

Answer 8

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