Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CHEM 212 > Midterm 2 (CH 17-19) > Flashcards

Midterm 2 (CH 17-19) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

When a chemical system is at equilibrium:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which of the following has an effect on the magnitude of the equilibrium constant?
A)Removing products as they are formed
B)Adding more of a reactant
C)Adding a Catalyst
D)Increasing the pressure, in a gas-gas reaction
E)Change in temperature

A

E)Change in temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which of the following is a strong acid?
A)H2CO3
B)H2SO3
C)H2SO4
D)H3PO3
E)CH3COOH

A

C)H2SO4

Strong acids include the hydrohalic acids (HCl, HBr, HI) and oxoacids in which the number of oxygen atoms exceeds ionizable protons by two or more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which of the following acids has the lowest pH?

0.1 M HBO, pKa = 2.43

0.1 M HA, pKa = 4.55

0.1 M HMO, pKa = 8.23

0.1 M HST, pKa = 11.89

pure water

A

HBO (lowest pKA = strongest acid = highest Ka)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the pH of a 0.20 M HCl solution?

A

B) 0.70

pH=-log(H3O+)
pH= -log (.2) because HCl fully dissociates in aqueous environments and therefore [H3O+] = .2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the pH of a 0.0035 M KOH solution?

A

E)11.54

pOH=-log[OH-] pH + pOH = 14
pOH=-log[.0035]= 2.46

14-2.46=pH
pH=11.54

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the [OH−] for a solution at 25°C that has [H3O+] = 2.35 × 10−3 M?

A

C)4.26 x 10^-12

[H3O+] x [OH-] = 1x10^-14

[OH-]= (1x10^-14)/(2.35x10^-3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the [H3O+] for a solution at 25°C that has pOH = 5.640?

A

C)4.37x10^-9

pH+pOH=14
14-5.640=8.36

10^-pH = [H3O+]
10^-8.36=[H3O+]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Butyric acid is responsible for the odor in rancid butter. A solution of 0.25 M butyric acid has a pH of 2.71. What is the Ka for the acid?

A

D)1.5x10^-5

CH3CH2CH2COOH = butyric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the value of Kb for the cyanide anion, CN−? Ka(HCN) = 6.2 × 10−10

A

B)1.6 × 10−5

Kw=Ka x Kb Kw=1x10^-14

(1x10^-14)/(6.2x10^-10) = 1.6x10^-5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which of the following aqueous liquids is the most acidic?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

A solution is prepared by adding 0.10 mol of sodium fluoride, NaF, to 1.00 L of water. Which statement about the solution is correct?

A

A) The solution is basic

NaF + H2O -> Na+ F- Solution will be basic as there are no acidic ions to balance the basicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

A solution is prepared by adding 0.10 mol of iron(III) nitrate, Fe(NO3)3, to 1.00 L of water. Which statement about the solution is correct?

A

C)The solution is acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which of the following is considered a Lewis acid?

A

Lewis acid = lone pair acceptor. Must have an atom that has an empty orbital to accept electrons.

B)BCl3 Boron has empty p orbitals and can accept the lone pairs

30
Q

Which one of the following is a Lewis acid but not a Brønsted-Lowry acid?

A

A)Fe3+

Lewis Acid is a lone pair acceptor whereas Brønsted-Lowry acid donates a proton in aqueous solution and must have a proton in the formula. Fe3+ is a Lewis Acid but doesn’t have a proton to donate and therefore is not a Brønsted-Lowry Acid

31
Q

Which of the following aqueous mixtures would be a buffer system?

A

D)H3PO4, H2PO4−

Buffer system consists of an acid and its conjugate base

32
Q

Which of the following has the highest buffer capacity?

A

0.50 M H2PO4−/0.50 M HPO42−

-Buffer capacity is best at 1:1 ratio of acid and conjugate base
-0.5M + 0.5M

33
Q

A solution is prepared by adding 500 mL of 0.3 M NaClO to 500 mL of 0.4 M HClO. What is the pH of this solution?

A
34
Q

What is the pH of a buffer that consists of 0.45 M CH3COOH and 0.35 M CH3COONa?
Ka = 1.8 × 10−5

A
35
Q

What is the pH of a buffer that consists of 0.20 M NaH2PO4 and 0.40 M Na2HPO4?
For NaH2PO4, Ka = 6.2 × 10−8

A

pH=7.51

36
Q

You need to use KH2PO4 and K2HPO4 to prepare a buffer with a pH of 7.45. Which of the following ratios of [base]/[acid] is required? For phosphoric acid, (H3PO4), Ka2 = 6.2 × 10−8.

A
37
Q

At the equivalence point in an acid-base titration:

A

The moles of acid = moles of base

ensure that it is in stoichiometric ratio

38
Q

When a strong acid is titrated with a strong base, the pH at the equivalence point:

A

is equal to 7.0

39
Q

When a weak acid is titrated with a strong base, the pH at the equivalence point:

A

is >7.0

40
Q

When a strong acid is titrated with a weak base, the pH at the equivalence point

A

is < 7.0

41
Q

Describe the titration curve of a weak acid and weak base

A

Equivalence point depends on relative concentrations of each.

42
Q

Describe the titration curve of a polyprotic acid

A

Multiple equivalence associated with the different Ka values for each acidic proton

43
Q
A
44
Q

The indicator propyl red has Ka = 3.3 × 10−6. What would be the approximate pH range over which it would change color?

A

pH of an indicator = +/- pKa
pKa=-log(3.3x10^-6)= 5.48
pH= 4.5-6.5

45
Q

A 50.0-mL sample of 0.50 M HCl is titrated with 0.50 M NaOH. What is the pH of the solution after 28.0 mL of NaOH have been added to the acid?

A
46
Q

Write the ion product expression for calcium phosphate, Ca3(PO4)2.

A
47
Q

The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the Ksp for Ag2CrO4?

A
48
Q
A
49
Q
A
50
Q
A
51
Q
A
52
Q
A
53
Q
A
54
Q
A
55
Q
A
56
Q
A
57
Q
A
58
Q
A
59
Q
A
60
Q
A
61
Q
A
62
Q
A
63
Q
A
64
Q
A
65
Q
A
66
Q
A
67
Q
A
68
Q
A
69
Q
A
70
Q
A

CHEM 212 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions