Unit 2: Chemical Equilibrium

Question 1

Equilibrium constant

Answer 1

K, it is unitless.

Question 2

Rate constant

Answer 2

k

Question 3

In equilibrium are the concentrations of products and reactants the same?

Answer 3

No, the concentrations of products and reactants are just constant.

Question 4

What can effect the equilibrium constant?

Answer 4

Change in temperature

Question 5

What is heterogeneous equilibria

Answer 5

Reactions with species that are different phases.

Question 6

What does not appear in an equilibrium constant equation?

Answer 6

Pure solids, liquids, and solvents

Question 7

Large K?

Answer 7

> 10^3

Question 8

Intermediate K?

Answer 8

10^-3 to 10^2

Question 9

Small K?

Answer 9

<10^-4

Question 10

What happens with a large K?

Answer 10

The reaction proceeds to completion and at eq there will be a large amount of product and a small amount of reactant.

Question 11

What happens with a small K?

Answer 11

The reaction does not completely proceed and at eq there will be a small amount of product and a large amount of reactant.

Question 12

Reaction Quotient

Answer 12

Q

Question 13

If Q < K what happens?

Answer 13

The reaction will go towards the products and the Q will get larger.

Question 14

If Q > K what happens?

Answer 14

The reaction will go towards the reactants and the Q will get smaller.

Question 15

What happens if you increase the concentration of a substance?

Answer 15

The reactions shifts away from that substance.

Question 16

What happens if you decrease the concentration of a substance?

Answer 16

The reaction shifts towards that substance.

Question 17

What happens if you increase the pressure of the system?

Answer 17

The reaction shifts towards the side with fewer moles.

Question 18

What happens if you decrease the pressure of the system?

Answer 18

The reaction shifts towards the side with more moles.

Question 19

What happens if you increase the temperature of the system?

Answer 19

The reaction shifts away from the heat/energy.

Question 20

What happens if you decrease the temperature of the system?

Answer 20

The reaction shifts towards the heat/energy

Question 21

What happens if you add a catalyst to the system?

Answer 21

Nothing

Question 22

What are the steps for solving an intermediate K problem?

Answer 22

1. Calculate Q to determine the direction of the reaction.
2. Make ICE table.
3. Substitute into K and solve for x.

Question 23

When solving a large K reaction should you let it go forward to completion?

Answer 23

Yes, this way it becomes a limiting reagent type problem.

Question 24

What are the 6 strong acids?

Answer 24

HCl, HBr, HI, HNO3, HClO4, H2SO4

Question 25

What is a polyprotic acid?

Answer 25

Acids that have several protons which can be donated.

Question 26

What is the leveling effect?

Answer 26

The inability to tell the difference between the strength of strong acids in solvents like water or with a higher pH.

Question 27

What is a buffer?

Answer 27

A solution that contains a considerable amount of a weak acid and its conjugate base. They resist changes in pH when an acid or base is added to a solution.

Question 28

How can a buffer be prepared?

Answer 28

Partial neutralization: The addition of a strong acid or base to one component of the buffer.

Question 29

What is an equation for pKa?

Answer 29

-log[Ka]

Question 30

What is buffer capacity?

Answer 30

The measure of the buffer's ability to maintain pH.

Question 31

What is buffer range?

Answer 31

The pH range where the buffer is effective.

Question 32

What is Solubility?

Answer 32

The amount of solid that must be dissolved to produce a solution

Question 33

What is precipitation?

Answer 33

When and how much solid will precipitate out of a solution.

Question 34

What is the solubility product?

Answer 34

Ksp.

Question 35

What is a saturated solution?

Answer 35

A solution with the maximum concentration of dissolved ions, with the solution in contact with extra undissolved solid.

Question 36

When Q > Ksp?

Answer 36

The reaction proceeds towards reactants and precipitation is formed.

Question 37

When Q < Ksp?

Answer 37

The reaction proceeds towards products and no precipitation is formed.

Question 38

What is the common-ion effect?

Answer 38

It is the effect on an equilibrium involving a substance that ads an ion that is a part of the equilibrium.

Question 39

When Q = Ksp?

Answer 39

The solution is saturated.

Question 40

What are the 4 rules of solubility?

Answer 40

1. Nitrate salts 2. Alkali metals and ammonium salts 3. Cl, Br, and I salts except with: Ag, Pb, and Hg2 4. Sulfate salts except with: Sr, Ba, Pb, Hg2

Question 41

What are the 4 rules of insolubility?

Answer 41

1. Hydroxide salts 2. Sulfide salts 3. Carbonate salts 4. Phosphate salts all except with: group 1 and NH4 salts

Question 42

Will basic salts be more soluble in acidic solutions?

Answer 42

Yes

Question 43

What is a complex ion?

Answer 43

A central metal ion with several groups attached.

Question 44

What is Kf?

Answer 44

The formation constant

Question 45

How does adding H3O+ affect the solubility of anion of a weak acid?

Answer 45

It increases it solubility.