Chemical Kenetics

Question 1

Describe the collision theory and how it applies to chemical reactions

Answer 1

Collision theory states that a chemical reaction can only occur between particles when they collide

Question 2

Describe the effects of changes in surface area of a solid on the rate of a
reaction and use the collision theory to explain why

Answer 2

Reducing particle size and increasing the relative surface area means that there are more successful collisions and a faster rate of reaction

Question 3

Describe the effects of changes in temperature on the rate of a reaction
and use the collision theory to explain why

Answer 3

When the temperature is raised, particles move faster and collide frequently, collisions are successful, therefore causing the rate of reaction increase

Question 4

Describe the effects of changes in concentration on the rate of a reaction
and use the collision theory to explain why

Answer 4

When the concentration is increased, particles are more crowded together and collide frequently, collisions are successful, therefore the rate of reaction increases

Question 5

Describe the effect of a catalyst on a reaction rate

Answer 5

A catalyst lowers the amount of energy needed for a successful collision, there are more collisions, therefore causing a faster reaction

Question 6

Describe experiments to investigate the effects of changes in surface area
of a solid, concentration of solutions, temperature and the use of a
catalyst on the rate of a reaction

Question 7

Explain that a catalyst speeds up a reaction but is not a reactant itself

Answer 7

A catalyst speeds up a chemical reaction by lowering the activation energy needed for the reaction to occur. It doesn’t participate as a reactant and is not consumed in the process. The catalyst provides an alternative pathway that requires less energy for the reaction to occur, forming a temporary intermediate that breaks down to form the products of the reaction. Catalysts can be re-used many times.