Chapter 2: Chemical Equilibrium

Question 1

the term that describes a situation where microscopic changes occur but macroscopic do not, because forward and reverse reaction rates are equal.

Answer 1

Dynamic equilibrium.

Question 2

What must there be for an equilibrium to exist

Answer 2

a closed system

Question 3

What are the 7 characteristics of a system in equilibrium?

Answer 3

1. The system is closed
2. Opposite reactions occur at the same rate.
3. Equilibrium was reached.
4. The concentration of products/reacts are constant.
5. Macroscopic properties remain constant.
6. Temperature is constant.
7. The reaction started with either reactants or products.

Question 4

What says that if a closed system at equilibrium is subject to a change, a process will occur to counteract that change.

Answer 4

Le Châtelier’s Principle

Question 5

What, surprisingly, does not affect the position of an equilibrium?

Answer 5

Catalysts.

Question 6

If you add heat to a system, how will it shift?

Answer 6

In a way to use up the heat (away from heat)

Question 7

If you remove heat from a system, how will it shift?

Answer 7

To produce heat (towards heat)

Question 8

If you increase the concentration of a substance in an equilibrium, how will it shift?

Answer 8

To reduce concentration (shift away from substance).

Question 9

If you decrease the concentration of a substance in equilibrium, how will it shift?

Answer 9

To increase concentration (towards substance).

Question 10

If you total pressure is increased, what will happen?

Answer 10

Shift towards side with least moles of gas (as shown by coefficients).

Question 11

If the total pressure is decreased, what will happen?

Answer 11

Shift towards side with more moles of gas (as shown by coefficients).

Question 12

If the pressure of a particular substance is increased, what will happen?

Answer 12

Shift away from that substance.

Question 13

How do you alter the concentration of certain ions in equilibrium?

Answer 13

By adding solutions that contain that ion in it, or solutions that will combine with that ion in a certain ratio.

Question 14

When an equilibrium shifts, the amount each substance shifts depends on what?

Answer 14

Mole ratios.

Question 15

An equilibrium graph represents what exactly?

Answer 15

How each substance in an equilibrium shifts to accomodate a change and reach an equilibrium again.

Question 16

What is done to solve the problem in the Haber Process

Answer 16

Moderate temperature and high pressure.

Question 17

What is a spontaneous reaction?

Answer 17

A reaction that occurs by itself, without interference.

Question 18

Most spontaneous reactions are what type of reaction?

Answer 18

Exothermic, because it does not always require activation energy.

Question 19

Why is it unlikely that a spontaneous reaction would be endothermic?

Answer 19

Because endothermic reactions require significant activation energy to react.

Question 20

How are endothermic reactions still sometimes able to be spontaneous?

Answer 20

Through randomness.

Question 21

Which word describes the amount of randomness in a system?

Answer 21

Entropy

Question 22

What can generally be said about the entropy of a system?

Answer 22

It is favoured over ordered states, shifts towards most random side.

Question 23

What is the symbol for entropy?

Answer 23

Delta-S

Question 24

What are the two factors that determine spontaneity?

Answer 24

Enthalpy and Entropy.

Question 25

What is the tendency for enthalpy in a system?

Answer 25

Tends towards minimum enthalpy, will shift towards side with heat term. (product side in exothermic and reactant side in endothermic)

Question 26

What are the states’ level of randomness, from least to most?

Answer 26

Solids, liquids, aqueous, gas

Question 27

If a system is in one phase, which side is the most random?

Answer 27

The side with the most molecules.

Question 28

If a system has the same amount of particles, which side is most random?

Answer 28

The side with the most random phase.

Question 29

The equilibrium constant (Keq) is dependant on what?

Answer 29

The temperature.

Question 30

Which states are not included in Keq calculations?

Answer 30

pure solid and pure liquid.

Question 31

Does adding a solid or liquid to a system change the equilibrium?

Answer 31

No

Question 32

What does a large Keq value imply?

Answer 32

Large amount of products present at equilibrium.

Question 33

What does a small Keq value imply?

Answer 33

A small amount of products present at equilibrium.