Acids and Bases

Question 1

what is an Arrhenius acid

Answer 1

H in the formula
dissociates to = H30
HCl, HNO3

Question 2

Arrhenius Base

Answer 2

A substance with OH in the formula - dissociates in water to release OH–
NaOH, KOH, LiOH

Question 3

what is the issue with Arrhenius

Answer 3

not all acids and base have a H or OH
the definition is very limited

Question 4

Bronsted-Lowry Acid

Answer 4

proton donor
must have H in the formula to donate H
All Arrhenius acids = bronsted lowry

Question 5

Bronsted-Lowry Base

Answer 5

proton acceptor (H+)
- must have a lone pair to accept the H+
All Arrhenius bases = bronsted-lowry based

Question 6

what does it mean to be amphiprotic

Answer 6

a substance that acts both as a base and an acid

Question 7

the acid will donate an H+ to the other reactant to form a conjugate ____

Answer 7

base

Question 8

T/F all conjugates are weaker than the original base

Answer 8

true

Question 9

a weaker acid has a _____ conjugate base
a stronger acid has a _____ conjugate base

Answer 9

stronger
weaker

Question 10

what is autoionization

Answer 10

h2o + h2o = h3o + oh
in pure water the concentrations of the products are equal
these water molecules spontaneously react with each other to form ions without any external influence

Question 11

what is kw

Answer 11

Kw = [H3O][OH] = 1.0 x 10-14 at 25*C
higher H3O = lower OH (when acid)
higher OH = lower H30 (when base)

Question 12

pH

Answer 12

pH = 7 = neutral
pH > 7 = basic
pH < 7 = acidic
pH = -log [H3O]

Question 13

pOH

Answer 13

pH = 7 = neutral
pH > 7 = acidic
pH < 7 = basic
pOH = - log [OH]

Question 14

what is pKw

Answer 14

pKw = -log(Kw)

Question 15

when Kw increases, pKw ____

Answer 15

decreases

Question 16

when Kw decreases, pKw ________

Answer 16

increases

Question 17

what are strong acids/bases

Answer 17

dissociate completely into their ions in water
HA + H2O –> H3O + A
only for strong acids [HA] = [H3O] –> solve pH
HB + H2O –> B + OH
only for strong bases [HB] = [OH]

Question 18

what are hydrohalic acids

Answer 18

hydrogen + halogen
HCl, HBr, HI

Question 19

what are oxoacids

Answer 19

oxygen + hydrogen + another element
HNO3, H2SO4, HClO4

Question 20

what is a list of all the strong acids memorize

Answer 20

HCl
HBr
HI
HNO3
HClO4
H2SO4

Question 21

what is a list of all the strong bases memorize

Answer 21

LiOH
NaOH
KOH
RbOH
CsOH
Ca(OH)2
Sr(OH)2
Ba(OH)2

Question 22

what is the acid dissociation constant

Answer 22

Ka
- the magnitude of Ka = how much the reaction has proceeded to the products to each equilibrium
- weak acids = low Ka = high pKa = more reactants
- strong acids = high Ka = low pKa = more products
Ka = [H3O][A–]/[HA] → products/reactants
–> Don’t include water

Question 23

Percent HA dissociation

Answer 23

HA diss = [HA] that dissociated / [HA] Initial

Question 24

what is a binary acid

Answer 24

a compound composed of hydrogen and a non-metal
HCl

Question 25

how can you tell the strength of a Binary Acid

Answer 25

1. how EN the central non-metal is - more EN = more polar bond - electron density cloud shifts to the Cl, loosening the hold of the H atom --> this makes it easier for H+ to release --> makes more acidic 2. the strength of the bond between the H and the non-metal - the bond strength depends on how good the hold of H is, the less hold = more acidic - the larger the atom is, the less bond strength it has

Question 26

as EN increases, ____ increases As bond strength decreases, ____ increases

Answer 26

acidity acidity

Question 27

bond strength periodic trend

Answer 27

The bond strength decreases down a group because the atomic radius increases, making those atoms down the group much larger - less attraction with the nucleus = less hold on the H Acid strength = HF < HI Because iodine = bigger molecule F is just very electronegative but very small so it has a strong bond strength

Question 28

EN periodic trend

Answer 28

increases as you go to the left fluorine = most EN = most polar

Question 29

how can you tell the strength of an oxoacid

Answer 29

1. the EN of the central non-metal - the more the central atom = EN the more the O--H bond becomes polar, and O gets attracted to the central atom, while H+ releases = acidity **Use this method only if you are comparing oxoacids with the same number of atoms 2. the number of O atoms - more O atoms = more joining of electron clouds with the central atom = looser hold on H+ = more acidic inc Oxygen = inc acidity

Question 30

if the charge of a metal = higher, it resulted in a ____ acid

Answer 30

strong acid Al3+ = more acidic than Na+ which is neutral

Question 31

if the molecule is ____ the better hold it has on the H+ and prevents it from making an acidic solution

Answer 31

small, and highly charged

Question 32

the lower pKb / pKa = ____ acid/base

Answer 32

stronger stronger base --> more OH dissociation --> higher Kb --> lower pKb

Question 33

if Ka is larger than the Kb = ____, therefore they are ____ proportional

Answer 33

small, inversely

Question 34

how is Kb and Ka related

Answer 34

pKa + pKb = 14 you get the pK's by doing -log(Ka/b)

Question 35

T/F when a neutralization reaction occurs, a salt is formed but sometimes the salt can react further with water and affect the pH of the solution

Answer 35

true

Question 36

does the cation of a strong base (salt) affect the pH?

Answer 36

no the salt of a strong base does not react with water, they are already hydrated and not charged enough to undergo another reaction = Ca, Na, Li, Cs, Fr

Question 37

cation

Answer 37

+ charge will come from a base = conjugate acid

Question 38

anion

Answer 38

- charge will come from an acid = the conjugate base

Question 39

does the cation of a weak base affect pH

Answer 39

NH3 + H2O --> NH4+ + OH- NH4+ + H2O --> NH3 + H3O+ this makes the solution slightly acidic and decreases the pH slightly

Question 40

how do the cations that are charged metal ions impact the pH

Answer 40

small and highly charged metals will steal the electron density from the OH bond and release the H+ - making the pH slightly acidic, decreasing it, making a weak base

Question 41

how does the anion of a strong acid impact the pH

Answer 41

HCl + H2O --> Cl- + H3O the Cl = anion = saturated - does not react with water further, considered a spectator ion

Question 42

how do anions from weak acids impact the pH

Answer 42

they are the conjugate bases HA + H2O ---> H3O+ + A- A- + H2O --> HA+ OH- this makes the solution slightly basic, and increases the pH

Question 43

what is the levelling effect

Answer 43

Water exerts a levelling effect on any strong acid or base by reacting with it to form the products of water autoionization (H3O or OH)

Question 44

Lewis Acid-Base Definition

Answer 44

base = species that accepts an electron pair to form a bond acid = a species that donates an electron pair to form a bond acid + base = adduct adduct = a species with a new covalent bond