C6- Rates Of Reaction

Question 1

How is rate of reaction calculated?

Answer 1

Amount of reactant used / time taken

OR

Amount of products formed / time taken

Question 2

What 4 factors affect rate of reaction?

Answer 2

-temperature
-concentration/pressure
-surface area
-catalysts

Question 3

What are the various units for rate of reaction?

Answer 3

Can include g/s or cm³/s or mol/s

Generally, mass/time, volume/time, moles/time

Question 4

Describe and explain the effect of increasing concentration on the rate of reaction

Answer 4

If the concentration increases there will be a faster reaction
This is because there will be more reactants, which means that more frequent collisions will occur.

Question 5

Describe and explain the effect of increasing surface area on the rate of reaction

Answer 5

Increasing the surface area of solid reacts increases the frequency of collisions which would increase the rate of reaction

Question 6

What is a catalyst and how does it affect the rate of reaction?

Answer 6

A catalyst changes the rate of reaction but is not used up.

Increases the rate of reaction by providing a different pathway for the reaction that has a lower activation energy

Question 7

Describing explain the effect of increasing temperature on the rate of reaction

Answer 7

If the temperature increases there’ll be a faster rate of reaction.

This is because when the temperature increases, the kinetic energy of the particles increases therefore more collisions occur between particles.

Question 8

Describe Le Chateliers principle

Answer 8

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

Question 9

Describe the effect of changing temperature on the position of the equilibrium

Answer 9

If the temperature of the system at equilibrium is increased:

-The relative amount of products are equilibrium increases for an endothermic reaction

-The relative amount of products that equilibrium decreases for an exothermic reaction

Question 10

What happens when the concentration of a reactant is increased?

Answer 10

More products will be formed until equilibrium is reached again.

Question 11

What occurs if the concentration of a product is decreased?

Answer 11

More reactants will react until equilibrium is reached again.

Question 12

What is the effect of changing the concentration of reactants or products on equilibrium?

Answer 12

The system is no longer at equilibrium and the concentrations of all substances will change until equilibrium is reached again.