Rate of Reaction & Reversible Reactions

Question 1

What is the speed of a reaction called?

Answer 1

The rate.

Question 2

What are the factors that increase the rate of reaction?

Answer 2

Catalyst, Concentration/Pressure, Surface Area and Temperature.

Question 3

What is a Catalyst?

Answer 3

A substance that increases the speed of a reaction and cannot be used up.

Question 4

Are reversible reactions endothermic or exothermic?

Answer 4

They are endothermic in one way an exothermic in the other.

Question 5

How can reaction rates be changed?

Answer 5

When the reaction conditions change.

Question 6

What is Collision Theory?

Answer 6

Collision theory says that a reaction will only take place when particles collide with sufficient energy.

Question 7

What is activation energy?

Answer 7

The smallest amount of energy needed to cause a reaction.

Question 8

What is the rate of a reaction?

Answer 8

How fast the reactants are changed into products.

Question 9

What must particle do in order to react?

Answer 9

Collide with sufficient energy.

Question 10

What does this (⇌) symbol mean?

Answer 10

The reaction is reversible

Question 11

What is a reversible reaction?

Answer 11

A reaction that can be reversed.

Question 12

Here is a reaction: A + B ⇌ C + D
a) What type of reaction is this?
b) What is the reaction of A + B called?
c) What is the reaction of C + D called?

Answer 12

a) Reversible reaction
b) forward reaction
c) backward reaction

Question 13

What is Equilibrium?

Answer 13

The point at which the rates of the forward and backwards reactions (in reversible reactions) are the same.

Question 14

How do Catalysts speed up a chemical reaction?

Answer 14

Catalysts work by providing a different pathway for a reaction. The new pathway has a lower activation energy, so less energy is needed for the reaction to happen.

Question 15

What is the equation for mean rate of reaction (product formed)?

Answer 15

mean = product formed / time

Question 16

What is the equation for mean rate of reaction (reactant used)?

Answer 16

mean = reactant used / time

Question 17

How does the concentration/pressure of a reactant affect the rate of reaction?

Answer 17

The higher the concentration/pressure of a reactant is, the more particles will be able to collide. Using collision theory, this means that the rate of reaction will increase.

Question 18

On a graph, what does a steeper line show?

Answer 18

The rate increasing.

Question 19

On a graph, what does a flat line show?

Answer 19

The reaction has finished/stopped.

Question 20

What is the rate of a reaction determined by (collision theory)

Answer 20

The frequency of successful collisions.

Question 21

How does the surface area of a reactant increase the rate?

Answer 21

When reacting a solid with a solution/gas, the particles of the solution/gas can only react (collide) with particles on the surface of the solid. Increasing the surface area of the solid will provide a larger surface for the collisions to take place.

Question 22

What is Le Chatelier’s Principle?

Answer 22

If a system at equilibrium is subjected to a change, the system will adjust to counteract that change.

Question 23

Explain what is meant by; ‘Equilibrium lies to the right’

Answer 23

The concentration of products is greater than that of reactants.

Question 24

What are three factors that the position of equilibrium depends on?

Answer 24

• Temperature
• Pressure
• Concentration.