Chapter 8 - Equilibrium

Question 1

Homogenous equilibrium

Answer 1

A chemical system in equilibrium in which all of the components are in the same physical states

Question 2

Heterogenous equilibrium

Answer 2

A chemical system in equilibrium in which components are in different physical states

Question 3

Law of chemical equilibrium

Answer 3

In a chemical system at equilibrium, there is a constant ratio between the conc of the products and the conc of the reactants

Question 4

Dissociation

Answer 4

The process of breaking apart into smaller particles, such as ions or neutral particles

Question 5

Ionization

Answer 5

The process in which a charged particle (ion) is formed

Question 6

Arrhenius theory of acids-bases

Answer 6

• acids dissociate to release H+ (must contain H+ ions)
• bases dissociate to release OH- (must contain OH- ions)

Question 7

Bronsted- - Lowry theory of acids-bases

Answer 7

• acids act as proton donors
• bases act as proton acceptors

** water can act as both an acid and a base and is considered amphiprotic (can accept or donate a proton)

Question 8

Strong acid

Answer 8

An acid that dissociates completely into ions in water

ex. HBr, HCl, HI, HNO3, HCIO4

Question 9

Weak acid

Answer 9

An acid that ionizes to a limited extent in water

ex. HF, H3PO4, H2CO3, CH3COOH, etc

Question 10

Strong base

Answer 10

A base that ionizes completely in water

ex. NaOH, KOH, Ba(OH)2, Mg(OH)2, etc

Question 11

Weak base

Answer 11

A base that ionizes to a limited extent in water

ex. aniline, pyridine, hydrazine, quinine, etc.

Question 12

acidic salts

Answer 12

Contain the anion of a strong acid and the cation of a weak base
~ small highly charged metal ions as well (Al3+, Fe3+, Cr3+)

Question 13

How do we find the Ka of the conjugate acid of a weak base

Answer 13

Kw = Ka x Kb

Question 14

endpoint

Answer 14

the pH at which the indicator changes colour

Question 15

equivalence point

Answer 15

the point in a titration in which moles of acid are equal to moles of base

na = nb

Question 16

describe Keq numerically

Answer 16

if keq = 1, there are approximately equal concs of products & reactants

if keq > 1, product formation is favoured

if keq is < 1, reactant formation is favoured

Question 17

what is the equilibrium constant, Keq

Answer 17

the ratio of equilibrium conc for a particular chemical system at a particular temp (unitless)

Question 18

what type of system does equilibrium require

Answer 18

closed system

Question 19

chemical equilibrium

Answer 19

a state in a chemical system in which the forward and reverse reactions are occurring at the same rate

Question 20

dynamic equilibrium

Answer 20

a chemical system at equilibrium that is changing at the molecular level while its macroscopic properties remain constant

ex. N2 + 2H2 –> <– 2NH3

Question 21

open system

Answer 21

system can exchange energy and matter with the surroundings

Question 22

closed system

Answer 22

can exchange energy but not matter with the surroundings

Question 23

isolated system

Answer 23

cannot exchange energy or matter with the surroundings

Question 24

what happens when the conc of a product is increased

Answer 24

shift left

Question 25

what happens when the conc of a product is decreased

Answer 25

shift right

Question 26

what happens when the conc of a reactant is increased

Answer 26

shift right

Question 27

what happens when the conc of a reactant is decreased

Answer 27

shift left

Question 28

is Keq affected by conc changes

Answer 28

no

Question 29

what happens when pressure increases and volume decreases

Answer 29

total number of particles decrease aka it shifts towards the side with less particles

Question 30

what happens when pressure decreases and volume increases

Answer 30

total number of particles increase aka it shifts towards the side with more particles

Question 31

what happens when an inert gas is added

Answer 31

does not shift the equilibrium (inert gases = noble gases)

Question 32

is Keq affected by P/V changes

Answer 32

no

Question 33

what does a temp increase favour

Answer 33

favours the endothermic reaction (energy is reactant)

Question 34

what does a temp decrease favour

Answer 34

favours the exothermic reaction (energy is product)

Question 35

what happens to Keq when temp is increased in an endothermic system (endo in the forward direction)

Answer 35

Keq increases

Question 36

what happens to Keq when temp is increased in an exothermic system (exo in the forward direction)

Answer 36

decreases Keq

Question 37

does catalyst affect equilibrium

Answer 37

no, it does not shift it in any direction

Question 38

explain Qeq and its relation to equilibrium

Answer 38

if Qeq = Keq, the system is at equilibrium if Qeq is less than Keq, the system is not at equilibrium and it will shift RIGHT to make more products if Qeq is more than Keq, the system is not at equilibrium and it will shift LEFT to make more reactants

Question 39

what is the ion product constant of water, Kw?

Answer 39

the equilibrium constant for the autoionization of water Kw = 1.0 x 10^(-14) Kw = [H3O+][OH]

Question 40

what are conjugate acid-base pairs

Answer 40

two substances related by the gain or lose of a proton

Question 41

basic salt solutions

Answer 41

contains the anion of a weak acid and the cation of a strong base

Question 42

neutral salt solutions

Answer 42

contain the anion of a strong acid and the cation of a strong base

Question 43

what is a buffer solution?

Answer 43

a solution that resists changes in pH ~ contains a weak acid or weak base and its conjugate

Question 44

how is a buffer solution made

Answer 44

a buffer solution is made by either a weak acid and its conjugate base or a weak base and its conjugate acid (the concs have to be similar; same amount of it)

Question 45

whats a titration

Answer 45

procedure used to determine the conc. of a solution by reacting a known volume of that solution with a measured volume of a solution of known conc

Question 46

if a strong acid was titrated to equivalence with a strong base, what would the resultant pH be

Answer 46

7.00 (neutral)

Question 47

what happens when metal oxides react with water

Answer 47

they are basic in water

Question 48

what happens when nonmetal oxides react with water

Answer 48

they are acidic in water

Question 49

what happens to pH at equivalence in a titration between a strong acid and a weak base

Answer 49

the pH will be acidic