6.1.2 - Factors which affect the rate of chemical reactions

Question 1

Give 5 factors which could affect the rate of chemical reactions

Answer 1

• the concentration of reactants in solution
• the pressure of reacting gases
• the surface area of solid reactants
• temperature
• presence of catalysts

Question 2

How does increasing surface area of solid reactants affect rate of reaction?

Answer 2

-increases it

• increased SA:V ratio
• more frequent collisions as particles have a larger area to work on

Question 3

How does increasing concentration or pressure of reactants affect rate of reaction?

Answer 3

• increases it
• more concentrated solution - more particles in same volume
• increased pressure - same number of particles in a smaller space
• more frequent collisions

Question 4

How does increasing the temperature affect rate of reaction?

Answer 4

• increases it
• temperature increased, particles move faster
• moving faster = colliding more frequently
• also, the faster they move the more energy they have so more of the collisions will have enough energy to make the reaction happen.

Question 5

How does using a catalyst increase the rate of reaction?

Answer 5

Catalysts reduce the activation energy needed for a reaction to occur by providing an alterative pathway with a lower activation energy.

Question 6

What is a catalyst?

Answer 6

A substance that increases the rate of a reaction, without being used up in the reaction itself.

Question 7

What structures in the body are biological catalysts?

Answer 7

Enzymes - they catalyse reactions in living things