Rates of Reaction

Question 1

What is the rate of reaction?

Answer 1

The rate of reaction refers to the speed at which the products are formed from the reactants in a chemical reaction

Question 2

How do you calculate the mean rate of reaction?

Answer 2

time taken

Question 3

What is the collision theory?

Answer 3

Chemical reactions can only take place when the reacting particles collide with each other. The collisions must have sufficient energy.

Question 4

What is the rate of a chemical reaction determined by?

Answer 4

The frequency of successful collisions

Question 5

What does frequency mean?

Answer 5

Number of successful collisions per second

Question 6

What is the effect of Concentration on the rates of reaction?

Answer 6

If the concentration of reactants is increased, there are more reactant particles moving together. There will be more collisions and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.

Question 7

What is the effect of pressure on the rates of reaction?

Answer 7

If the concentration or pressure is increased: there are more reactant particles per unit volume there is a greater chance of the particles colliding, which leads to more successful collisions per second. the rate of reaction increases.

Question 8

What is the effect of surface area on the rates of reaction?

Answer 8

If the surface area of a reactant is increased: more particles are exposed to the other reactant. there is a greater chance of particles colliding, which leads to more successful collisions per second therefore the rate of reaction increases.

Question 9

What is the effect of temperature on the rates of reaction?

Answer 9

Temperature affects the rate of a reaction because increasing the temperature will increase the kinetic energy of the reactant particles and make the particles move faster. This results in more successful collisions between reactant particles and a faster rate of reaction

Question 10

What is the activation energy?

Answer 10

The minimum amount of energy that the particles must have in order to collide successfully.

Question 11

What does a catalyst do?

Answer 11

Catalysts increase the rate of chemical reactions by lowering the activation energy and provide an alternate pathway for the reaction.

Question 12

Are catalysts used up in reactions?

Answer 12

No

Question 13

Why are catalysts important in carrying out reactions quickly?

Answer 13

It allows us to carry out reactions quickly without needing to increase the temperature which saves money.

Question 14

What is a reversible reaction?

Answer 14

In some chemical reactions, the products of the reaction can react together to produce the original reactants.

Question 15

What happens if one side of the reversible reaction is exothermic in one direction?

Answer 15

It is endothermic in the opposite direction and the same amount of energy is transferred in each case.

Question 16

What is it meant by the equilibrium?

Answer 16

When at some point in the reaction the forward and the reverse reactions will take place at exactly the same rate.

Question 17

What is Le Chatelier’s Principle?

Answer 17

If a system is at equilibrium and a change is made to the conditions, then the system responds to counteract the change.

Question 18

What is the effect of concentration on reversible reaction or equilibrium?

Answer 18

Chemical equilibrium will shift towards the reactant when the concentration of product increases, less product is formed and the concentration of reactant increases as the concentration of product decreases.

Question 19

What is the effect of temperature on reversible reaction or equilibrium?

Answer 19

-When the forward reaction takes place, if energy is released and the temperature of the system increases which means when the reverse reaction takes place, energy is taken in and the temperature of the system decreases.
-However, if we increase the temperature of the system, then the equilibrium shifts to the left to reduce the temperature that is because the reverse reaction is endothermic so energy is taken in causing the temperature to fall.
-If we decrease the temperature of the system, then the equilibrium shifts to the right to increase the temperature that is because the forward reaction is exothermic so energy is released causing the temperature to increase.

Question 20

What is the effect of pressure on reversible reaction or equilibrium?

Answer 20

-If we increase the pressure of the reversible reaction at equilibrium, the position of the equilibrium shifts to the side with the smaller number of molecules.
-If we reduce the pressure, then the position of the equilibrium shifts to the side with the larger number of molecules.