Chapter 15: Chemical Equilibrium

Question 1

chemical equilibrium

Answer 1

when two equal and opposite reactions occur at the same time so there is no apparent change in the system

Question 2

dynamic =m

Answer 2

when the reactants and products are reacting at the same rate (pouring and empyting water into a bucket at the same rate)

Question 3

=m constant

Answer 3

K, a ratio that occurs when a reversible chemical equation reaches =m

Question 4

facts about =m constant

Answer 4

each reversible process has its own value; K changes with temperature; can be expressed in terms of concentrations, partial pressure, or both and have no units

Question 5

=m equation

Answer 5

products/reactants

Question 6

Q>K, the rxn proceeds

Answer 6

in reverse

Question 7

reaction quotient

Answer 7

Q, products/reactants expression for concentrations not necessarily at =m

Question 8

if K»1, then which direction is the rxn favored

Answer 8

product favored (there is much more product), =m lies to the right

Question 9

if K«1, then which direction is the rxn favored

Answer 9

reactant favored (there is much more reactant), =m lies to the left

Question 10

homogenous equilibria

Answer 10

when all reactants and products are in the same phase

Question 11

NOTE*

Answer 11

omit concentration terms for pure solids and liquids when finding K

Question 12

if the original equation is multiplied by a number, then…

Answer 12

the new =m constant is the original =m constant raised to the same number

Question 13

solubility product constant suggest that solubility are favored in which direction?

Answer 13

reactant favored, Ksp«1

Question 14

what is Ksp?

Answer 14

an =m established between an undissolved solid and ions in a solution
(insoluble salt(s)–>ions(aq))
(or hydroxide or oxide)

Question 15

molar solubility

Answer 15

number of moles of the solute that dissolve in forming 1L of a saturated solution (units: mol/L; often the solvent is water

Question 16

units for mass solubility

Answer 16

g/L

Question 17

units for molar solubility

Answer 17

mol/L

Question 18

when solving for molar solubility, you are solving for…

Answer 18

s

Question 19

determining which compound is better soluble

Answer 19

you must calculate s and compare that; not Ksp

Question 20

1:1

Answer 20

square root of Ksp

Question 21

1:2, 2:1

Answer 21

cube root divided by 4

Question 22

1:3, 3:1

Answer 22

4th root divided by 27

Question 23

2:3,3:2

Answer 23

5th root divided by 108

Question 24

Le Chateliers’s Principle

Answer 24

when a system at =m is disturbed by a stress (change in concentration, pressure, temperature), the =m shifts in a direction that tends to reduce the effects of that stress

Question 25

if products are removed

Answer 25

the reaction proceeds towards the products to make more (K is kept constant but Q changes)

Question 26

is reactants are increased

Answer 26

the reaction proceeds forwards to make more products to compensate (K is constant and Q changes)

Question 27

when dealing with pressure/volume changes,

Answer 27

the reaction shifts to whichever direction has fewer moles of gas

Question 28

what happens when more heat is supplied? (such as an exothermic rxn where heat is a product)

Answer 28

the rxn will try to use up the extra heat and the =m will shift to the left and K will decrease