Rates Of Reaction

Question 1

Signs of a Chemical Reaction

Answer 1

Smell, change in temperature, change in colour, turbidity, fizzing, change in mass

Question 2

Rate of Reaction

Answer 2

rate = product produced / time taken

Question 3

Calculating rate from a graph

Answer 3

gradient = change in y / change in x
With a curved graph, a drawn tangent can be used.

Question 4

Collision Theory

Answer 4

For a chemical reaction to start, the particles in the reactants must collide with enough energy.
The more ‘successful collisions’ there are, the higher the rate of reaction.

Question 5

Successful Collisions

Answer 5

For a successful collision to occur, the particles in the reactants must collide with energy that is greater than or equal to the activation energy of the reaction.

Question 6

Factors that affect Rate

Answer 6

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

Question 7

Catalysts

Answer 7

Catalysts speed up reactions but don’t get used up in the reaction. They work by providing an alternative pathway for the reaction which has a lower activation energy.