Rate Of Reaction

Question 1

What does the gradient of a graph of volume of gas vs time represent?

Answer 1

The rate of reaction

Question 2

When the gradient is zero what does that tell about the reaction

Answer 2

The reaction has stopped as all the reactants are used up

Question 3

How do you calculate the mean rate of reaction

Answer 3

Quantity of product formed / Time taken

Question 4

How do you calculate the rate of reaction at a given point

Answer 4

By drawing a tangent at the specific point

Question 5

How do you calculate the gradient (h)

Answer 5

Change in Y / Change in X

Question 6

What is collision theory

Answer 6

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

Question 7

What is the rate of reaction determined by

Answer 7

The frequency of successful collisions

Question 8

What does increasing the concentration do to the rate of reaction

Answer 8

It increases the rate of reaction because there are more particles to react with. Therefore more frequent collisions.

Question 9

What’s the relationship between the rate of reaction and concentration

Answer 9

The rate is proportional to the concentration

Question 10

What is meant by the term frequency

Answer 10

The number of successful collisions per second

Question 11

What part of the solid can particles react with

Answer 11

The surface of the solid

Question 12

What’s the effect of increasing the surface area on the rate of reaction

Answer 12

Rate increases because there are more particles available to collide with so more frequent collisions.

Question 13

What is required for there to be a successful collision

Answer 13

When collisions overcome the activation energy

Question 14

What does increasing the temperature do to the rate of reaction

Answer 14

Increase the rate of reaction

Question 15

Explain why increasing the temperature increases the rate of reaction

Answer 15

Particles move faster so the frequency of collisions increases AND The particles have more energy so more particles have more than the activation energy and collide successfully

Question 16

What is the relationship between the rate of reaction and temperature

Answer 16

They are proportional

Question 17

What is the role of catalysts

Answer 17

They increase the rate of reaction but aren’t used up during the reaction

Question 18

Why do catalysts increase the rate of reaction

Answer 18

Because they lower the activation energy by offering an alternative pathway for the reaction

Question 19

What are reversible reactions

Answer 19

When products can react to reform the original reactants

Question 20

If a reversible reaction is exothermic in one direction what is it in the opposite direction

Answer 20

Endothermic

Question 21

What is equilibrium

Answer 21

The point where the forward and reverse reactions take place at exactly the same rate

Question 22

What is Le Chatliers principal

Answer 22

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

Question 23

What happens when you increase the temperature of reversible reaction

Answer 23

The equilibrium shift to reduce the temperature by moving in the endothermic direction

Question 24

What does the pressure of a gas depend on

Answer 24

The number of molecules

Question 25

What happens if the pressure increases on a reversible reaction at equilibrium

Answer 25

The position of the equilibrium shift to the side of the smaller number of molecules