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

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

Collision theory

Answer 3

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

Question 4

Effect of concentration on reaction rate

Answer 4

As the concentration of reactant 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 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

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

Maxwell-Boltzmann distribution

Answer 7

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

Question 8

Rate of reaction

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, cm3/s or mol/s