Chapter 10: Acids and Bases

Question 1

An Arrhenius acid dissociates to form ____.

Answer 1

H+ ions

Question 2

An Arrhenius base dissociates to form ____.

Answer 2

OH-

Question 3

A Bronsted acid ____________ H+

Answer 3

donates

Question 4

A Bronsted base ____________ H+

Answer 4

accepts

Question 5

Bronsted-Lowry acids and bases always occur in pairs because the definitions requires what?

Answer 5

The transfer of a proton from the acid to the base, aka conjugate acid-base pairs

Question 6

A conjugate acid is ____.

Answer 6

a base with a hydrogen ion added to it

in the reverse reaction, it is the H+ donor, thus it is an acid

Question 7

A conjugate base is ____.

Answer 7

an acid with a hydrogen ion removed from it

in the reverse reaction, it accepts H+, thus it is a base.

Question 8

An ____________ species is one that reacts like an acid in a basic environment and like a base in an acidic environment.

Answer 8

amphoteric

Question 9

In the Bronsted-Lowry sense, an amphoteric species can either gain or lose a proton, making it ____________ as well

Answer 9

amphiprotic

Question 10

The partially dissociated conjugate base of a ________________ acid is usually amphoteric, e.g. HSO4-. The ____________ of certain metals, e.g. Al, Cr, Pb, Zn, are also amphoteric.

Answer 10

polyvalent; hydroxides

Question 11

Complex amphoteric molecules include amino acids that have a ____________ intermediate with both cationic and anionic character.

Answer 11

zwitterion

Question 12

Acids formed from anions with names that end in -ide have the prefix ________ and the ending ____.

Answer 12

hydro-
-ic

Question 13

Acids formed from oxyanions are called oxyacids.
If the anion ends in -ite (less oxygen), then the acid will end in ________. If the anion ends in -ate (more oxygen), then the acid will end with ____ acid.

Answer 13

-ous acid
-ic acid

Question 14

What is the only thing that can affect K_w?

Answer 14

temperature! just like any other equilibrium constant

Question 15

At temperatures above 298 K, K_{w will increase. Why?}

Answer 15

The autoionization reaction is endothermic

Question 16

Strong acids and bases do what in aqueous solutions?

Answer 16

Completely dissociate

Question 17

What do weak acids and bases do in aqueous solutions?

Answer 17

They partially dissociate

Question 18

The smaller the Kb or Ka, the (stronger/weaker) a base or acid is.

Answer 18

weaker

Question 19

Electronegative elements positioned near an acidic proton increase acid strength how?

Answer 19

they pull electron density out of the bond holding the acidic proton - this weakens proton bonding and facilitates dissociation

Question 20

Acids and bases may react with each other to form a salt and often (not always) water. This is a ____________ reaction.

Answer 20

neutralization

Question 21

In acid-base titrations, the equivalence point is reached when what?

Answer 21

the # of acid equivalents present equals the number of base equivalents, or vice versa

Question 22

THe point at which the indicator changes to its final color is not the equivalence point, but rather the ____________

Answer 22

endpoint

Question 23

Main differences between strong acid vs weak acid titration with strong base?

Answer 23

1. initial pH is greater
2. strong acid has steeper/sudden rise in pH
3. equivalence point is greater than 7

Question 24

Why do weak acid strong base titrations have pH > 7?

Answer 24

produces a weak conjugate base and even weaker conjugate acid - this means there are more OH- than H3O+

Question 25

A ____________ ____________ consists of a mixture of a weak acid and its salt (which is composed of its conjugate base and a cation) OR a mixture of a weak base and its salt.

Answer 25

buffer solution

Question 26

What are two major examples of buffers?

Answer 26

CH3COOH and CH3COO-Na+ NH3 and NH4+Cl-

Question 27

What is an important property of buffers?

Answer 27

Can resist changes in pH when small amounts of acid or base are added

Question 28

One of the most important buffers in the human body is the ________________ buffer system.

Answer 28

bicarbonate

Question 29

In metabolic acidosis, what occurs?

Answer 29

Increased breathing to deplete CO2 and shift the system to the left to reduce H+

Question 30

What would happen if concentrations of both the acid and its conjugate base were doubled in a buffer solution?

Answer 30

THe buffering capacity, or ability to which the system can resist changes in pH, would increase

Question 31

Oxidation is ________

Answer 31

loss of e-

Question 32

Reduction is ________

Answer 32

gain of e-

Question 33

An oxidizing agent causes what?

Answer 33

Causes an atom to be oxidized, and is itself reduced

Question 34

A reducing agent causes what?

Answer 34

Causes an atom to be reduced, and is itself oxidized

Question 35

Almost all oxidizing agents contain what?

Answer 35

oxygen or another strongly electronegative element

Question 36

What are some common oxidizing/reducing agents?

Answer 36

Question 37

________________ ____________ are assigned to atoms to keep track of redistribution of electrons during chemical reactions

Answer 37

Oxidation numbers

Question 38

What is the oxidation number of a free element?

Answer 38

Zero

Question 39

The oxidation number of a monatomic ion is equal to what?

Answer 39

The charge of the ion

Question 40

The oxidation number of Group VIIA is -1, except for when?

Answer 40

When combined with an element of higher electronegative. Example: Cl- is -1 in HCl, but it is +1 in HOCl

Question 41

Hydrogen is usually ____. However, it is ____ in compounds with less electronegative elements from Groups ____ and ____. Hydrogen is ____ in HCl, but ____ in NaH.

Answer 41

+1; -1; Groups IA and IIA +1, -1

Question 42

In most compounds, the oxidation number of oxygen is ____. Except in peroxides (O_{2^{2-), where oxygen is ____, and compounds with more electronegative elements like OF2, where oxygen is ____.}}

Answer 42

-2; -1, +2

Question 43

The sum of oxdiation numbers in a neutral compound should be ____

Answer 43

zero

Question 44

The sum of oxidation numbers of the atoms present in a polyatomic ion is equal to ____

Answer 44

the charge of the ion

Question 45

Oxidation number assumes ________ ________ of electrons in bonds, "awarding" the electrons to the more electronegative element.

Answer 45

unequal division

Question 46

Formal charge assumes ________ ________ of electrons in bonds, awarding one electron to each atom in the bond.

Answer 46

equal division

Question 47

When assigning oxidation numbers, start with what?

Answer 47

The known atoms

Question 48

What does assigning oxidation numbers accomplish?

Answer 48

Allows us to determine how many moles of each species are required for conservation of charge and mass, which is necessary to balance the equation

Question 49

How does the half-reaction method work?

Answer 49

Separate the redox reaction into two half-reactions, the oxidation part and the reduction part, then they are balanced separately

Question 50

________________ is a specific type of redox reaction in which an element undergoes both oxidation and reduction in producing its products.

Answer 50

disproportionation

Question 51

What is an example of disproportionation?

Answer 51

catalysis of peroxides by catalase