Equilibrium

Question 1

What is a reversible reaction?

Answer 1

A reversible reaction is when the products can react to reform the original reactants.

Question 2

What is a Equilibrium Reaction?

Answer 2

The products react together to reform reactants at the same time as the reactants are forming products.

Question 3

Name the 4 Characteristics of Equilibrium

Answer 3

dynamic, rate of forward and backward reaction are equal, the concentration of reactants and products are constant at equilibrium, it requires a closed system.

Question 4

Explain the Following Characteristic of Equilibrium: Dynamic

Answer 4

Molecules or ions of reactants and products are continuously reacting. Reactants are continuously being changed to products and products are continuously being changed to reactants.

Question 5

Explain the Following Characteristic of Equilibrium: Rate of Forward and Backward Reaction being Equal

Answer 5

Molecules or ions of reactants are becoming products and these products are becoming reactant at the same rate.

Question 6

Explain the Following Characteristic of Equilibrium: The Concentration of Reactants and Products Being Constant

Answer 6

The concentration remains constant as the forward and backward reactions equal.

Question 7

Explain the Following Characteristic of Equilibrium: Requires a Closed System

Answer 7

A closed system is one in which none of the reactants or products escapes from the reaction.

Question 8

Explain the 4 Factors that Impact Equilibrium

Answer 8

Concentration, Pressure, Temperature, Catalyst

Question 9

How does Concentration Affect Equilibrium?

Answer 9

When concentration of one or more reactants is increased the system is no longer in equilibrium. The position of equilibrium moves to the right. More products are formed.

Question 10

How does Pressure Affect Equilibrium?

Answer 10

Increase in pressure it moves to the fewer molecules side. This ensures more of that substance is formed. If there is an equal number of molecules of gas the position of equilibrium is not affected. Only molecules of gas count when determining the affect of pressure on equilibrium.

Question 11

How does Temperature Affect Equilibrium?

Answer 11

Position of equilibrium shifts towards products. More products formed.

Question 12

How does the Addition of a Catalyst Affect Equilibrium?

Answer 12

Increase rate of forward and reverse reactions. Do not affect position of equilibrium or K_c

Question 13

What is the Equilibrium Expression?

Answer 13

K_c = [Products] / [Reactants]

If there is a value in front of a certain element in that chemical equation you need to raise the concentration of that element to that value in front. It is also important to note that liquids and solids cannot be included when calculating K_c

Question 14

How does a Change in Concentration Impact K_c?

Answer 14

If all other conditions remain constant the value of K_c does not change.

Question 15

How does a Change in Pressure Impact K_c ?

Answer 15

If all other conditions remain constant the value of K_c does not change.

Question 16

How does a Change in Temperature Impact K_c ?

Answer 16

In an endothermic reaction (heat is absorbed), the temperature shifts in the direction of products. This results in more products being produced and therefore concentration of products increase and the temperature of the products to also increases. as well. To balance this out, the concentration of the reactants decreases as the temperature increases.

Question 17

Explain how the Graph of Rate vs Time will Look?

Answer 17

There will only be 2 lines (for forward and reverse reaction) and when the lines meet it can be deemed that equilibrium is reached. This is because it is rate against time, meaning when the rates are equal equilibrium will be reached.

Question 18

Explain how the Graph of Concentration against Time will Look?

Answer 18

Can have two or more lines depending on the number of products and reacts. Equilibrium will be reached when the lines on the graph begin to plateau. This is because concentration is constant at equilibrium.

Question 19

What is the RICE Acronym and What Does it Help Achieve?

Answer 19

RICE stands for Ratio, Initial Number of Moles, Change (-x and x) and Equilibrium. It is used to calculate the K_c when some vital variables are missing.

Question 20

What is the Reaction Quotient (Q)?

Answer 20

It is the ratio of products to reactants, calculated in the same way as K_c.

Question 21

What Does it Indicate if Q = K_c ?

Answer 21

The system is in equilibrium.

Question 22

What does it Indicate if Q is less than K_c ?

Answer 22

Less products more reactants, hence forward reactions will be favoured for the system to reach equilibrium.

Question 23

What does it Indicate if Q is greater than K_c ?

Answer 23

More products and less reactants, hence reverse reactions will be favoured for the system to reach equilibrium.

Question 24

What Does a Large Value of K_c Indicate?

Answer 24

Indicates the reaction goes towards completion. All reactants become products. Equilibrium lies to the right as there are more products than reactants at equilibrium.

Question 25

What Does a Small Value of K_c Indicate?

Answer 25

Indicates that the reaction only occurs to a small extent. Equilibrium lies to the left as there are more reactants than products at equilibrium.

Question 26

What does a K_c Value Close to 1 Indicate?

Answer 26

Significant concentrations of both reactants and products present at equilibrium. Equilibrium lies to the right as there are more products than reactants at equilibrium.