Unit Test 3: Ch.14 and part of 15

Question 1

Arrhenius Definition of Acids & Bases?
Lewis?
Bronsted Lowry?

Answer 1

Produces H+ in solution, OH- in solution. Limited definition
e- acceptor, e- donor
proton donor, acceptor

Question 2

conjugate acid base pairs?

rule?

Answer 2

every acid forms a conjugate base
every base forms a conjugate acid\

A strong acid/base forms a weak conjugate acid
A weak acid/base forms a stronger conjugate acid

Question 3

formula for Ka?

Answer 3

HA -><- H+ + A-

Ka = [A-][H+]/[AH]

Question 4

Strong acids ____ dissociate in an aq solution

Answer 4

completely

Question 5

Titration

Answer 5

addition of a measured volume of base of known M into an acid to be analyzed. Base is titrant, acid is analyte.

Question 6

equivalence point vs. endpoint

Answer 6

enough titrant has been added to react 1:1 w/ analyte. To indicate this we use indicator.

1 drop beyond that point

Question 7

Normality (N)?

for a mono/di/triprotic acid in respect to molarity?

Answer 7

equivalents/Liter

= molarity
2* M
3*M

Question 8

equivalent mass?

Answer 8

weight of acid used/# of acid equivalents

Question 9

oxyacids? organic acids?

Answer 9

acidic proton attached to an oxygen

contains a carboxylic acid functional group. (COOH)

Question 10

amphoteric? autoionization?

Answer 10

can behave like an acid or base

a rxn in which 2 like molecules react to form ions. Done by water often.

Question 11

Kw? what does it mean/formula

Answer 11

1.0*10^-14

for H₂O ⇔ H⁺ + OH^-

Kw = [H+][OH-]

Question 12

formula for pH? pOH? relate them

Answer 12

this easy

Question 13

rounding rule for pH?

Answer 13

the # of places after the decimal point in the pH equals # of sigfigs in concentration of H+

Question 14

Calculating pH of strong acids

Answer 14

easy asf. Acids completely dissociate and you can easily calculate [H+] from this

Question 15

practice calculating pH of weak acids…

Answer 15

problem #73a
interactive example 14.9
problem #83

Question 16

5% rule for approximations?

Answer 16

(x/[Reactant]₀)*100

if it is 5% or larger, solve quadratic!

Question 17

% dissociation of weak acids…

formula?

for a given weak acid, % diss becomes ____ as acid dilutes more
and [H+] ____

Answer 17

[Amount dissociated]/[Initial concentration] * 100

interactive example 14.10

larger
decreases

problem #85b, d

Question 18

Strong bases __ dissociate and are ___ electrolytes

Answer 18

completely, strong

Question 19

list all strong acids and bases.

Answer 19

Acids: HCl, HBr, HI, H2SO4, HNO3, HClO4
Bases:
Group 1A: NaOH, KOH, LiOH, RbOH, CsOH (all group but not Fr)
Group 2: Ca(OH)2, Ba(OH)2, Sr(OH)2

Question 20

Weak bases

General formula for base dissociation
Kb?

Answer 20

do not completely dissociate and form an equilibrium

B(aq) + H2O(l) ⇔ BH⁺(aq) + OH- (aq)

Kb = [BH+][OH-]/[B]

example 14.13
problem 109a

Question 21

all of our weak base rxns will be reacting with water to produce BH+ which is the _____ and OH- which is the ____. This is called:

Answer 21

conjugate acid
conjugate base
hydrolysis (destruction/removal of water)

Question 22

Calculating pH of a strong base

Answer 22

they fully diss., so we will do this the same way as a strong acid.
example 14.12

Question 23

Ka * Kb = ___

pKa = ?
pKb = ?

pKa * pKb = ___ = ___

Answer 23

Kw = 1.0 * 10^-14

-log(Ka)
-log(Kb)

pKw = -log(Kw) = 14.00

Question 24

Properties of salts that produce neutral solutions:

consist of cations of ___ bases and the anion of ___ acids and have 0 effect on [H+]. Reason why

Answer 24

strong, strong

because since strong acids and bases completely dissociate in water, if the cation binded to an OH- in the water or the anion binded to an H+ in water, it would quickly dissociate again

problem 133a

Question 25

properties of salts that produce basic solutions cation has ___ and whose anion is the conjugate base of a ___. Aqueous solution is basic why? sometimes you have to calculate Kb from ___ and ___ if you have the ___ from the acid in the products side, and not the Kb from your anion from the salt

Answer 25

neutral properties (strong base), weak acid cation will bind to an OH and quickly dissociate. Conjugate base of a weak acid will bind to an H+ and hold onto it longer, as weak acids hold onto their proton more and remove [H+], making solution basic. example 14.18 problem 133b Ka, Kw, Ka

Question 26

Effect of structure on acid-base behaviors A molecule containing H+ will donate if its bond is ____ due to ____ HF is a very ___ molecule, but will not donate due to its ___ bond CH4 will not donate due to ____ and ___ for oxyacids, acid strength ___ as oxygens on central atom increases. This is because___

Answer 26

polar, electronegativity differewnce polar, strong strong bond and non-polarity increases. they pull away electrons from the OH. table 14.7, 14.8, chapter 14.9 in general

Question 27

for polyprotic acids the first dissociation makes the ____, simplifying the problem greatly however, know how to calculate the concentrations of the anion w/ no H+ example 14.15 there are cases where you do have to calculate the [H+] contributed in the 2nd dissociation. This only happens with ____. This is due to _____. However, you only have to do it in ___ solutions since % dissociation goes up

Answer 27

significant [H+] contribution sulfuric acid. High solubility, only diprotic strong acid we have to know. dilute. ex 14.16, 14.17 problem 126, 125

Question 28

acidic metal salts they do not directly act as an acid, but it will dissociate to form ___. the hydrated ion can act as an ____. provide example and write equation in the example provided, the metal ___ the OH bonds in the H2O, making the hydrogens more acidic (refer to 14.9) than those in free H2O. Typically, the higher the charge, the ___ the hydrated ion acidity

Answer 28

hydrated ions. weak acid. Ex: AlCl3 -> Al(H2O)₆³⁺ and 3Cl- Al(H2O)₆³⁺(aq) ⇔ Al(OH)(H2O)₅²⁺(aq) + H⁺(aq) solve js like a weak acid! polarizes, stronger example 14.20, problem 143/144

Question 29

Salts that produce acidic solutions: anion is ___ and cation is ___

Answer 29

not a base/conjugate base of a strong acid conjugate acid of a weak base

Question 30

understand how to calculate Ka from Kb and vice versa. Example, calculate Ka of NH₄⁺ from Kb of NH₃

Answer 30

pretty easy Ka*Kb = Kw rearrange as needed use for conjugate acids & bases when placed in aqueous solutions

Question 31

Salts w/ acidic and basic ions... cation is conjugate acid of ____, and anion is conjugate base of ____ to determine whether dissolution makes solution acidic or basic...

Answer 31

a weak base a weak acid acidic if Ka of acid formed by salt is larger than Kb of base formed by salt basic of Kb is larger than Ka neutral if they are equal problem 146

Question 32

memorize table 14.6

Question 33

when adding a common ion to an acid or base the equilibrium shifts ____

Answer 33

left

Question 34

common ions in acidic or basic solutions ___ the percent dissociation

Answer 34

decrease

Question 35

Buffer solution

Answer 35

weak acid & its conjugate base solution, resistant to pH changes when SMALL amounts of a strong acid or base are added

Question 36

buffer capacity

Answer 36

amount of acid or base the buffer can neutralize before pH begins to change to an appreciable degree

Question 37

Two ways to make buffers

Answer 37

weak acid w/ a salt of conjugate base weak base w salt of conjugate acid

Question 38

how would CH3COOH -><- CH3COO- + H+ act as a buffer?

Answer 38

if OH- is added, CH3COOH + OH- -> H2O + CH3COO- if H+ is added, CH3COO- + H+ -> CH3COOH interactive examples 15.2 and 15.3

Question 39

henderson - hasselbach equation (do not need to memorize) what is it used for?

Answer 39

for HA -><- A- + H+ pH= pKa + log([A-]/[HA]) used to calculate pH of a solution w/ known [A-] and [HA], useful for buffering solutions #43 look at interactive examples?