South Pasadena • Honors Chemistry
Name
4 · Salts and Solutions
Period
Date
UNIT TEST
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PRACTICE
You may use a pencil, eraser, and scientific calculator to complete the test.
You will be given a periodic table. The solubility rules are listed at the end of the test. No other resources are
allowed.
Please transfer your answers for Multiple Choice and Matching questions onto the Answer Document. Work
for these questions will not be graded. However, sufficient and appropriate work must be shown for the Free
Response questions in order to receive full credit.
SECTION 1: A, B, or C. Determine whether each description refers to an acidic, basic, or neutral solution.
(1 point each)
(A)
(B)
(C)
1. Is purple with cabbage juice.
Acidic
Basic
Neutral
2. Has a pH > 7.0.
Acidic
Basic
Neutral
3. Often tastes bitter.
Acidic
Basic
Neutral
4. Lye (drain cleaner).
Acidic
Basic
Neutral
5. A solution of HNO3.
Acidic
Basic
Neutral
6. [H+] = [OH–].
Acidic
Basic
Neutral
SECTION 2: TRUE/FALSE. (1 point each)
Evaluate the statement in column 1. If it’s TRUE, fill in bubble A. If it’s FALSE, fill in bubble B.
Evaluate the statement in column 2. If it’s TRUE, fill in bubble C. If it’s FALSE, fill in bubble D.
If column 2 is the correct explanation for column 1, then bubble E.
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If both columns are TRUE, but column 2 is the correct explanation, bubble ACE.
If both columns are TRUE, but column 2 is not the correct explanation, bubble AC.
If column 1 is TRUE and column 2 is FALSE, bubble AD.
If column 1 is FALSE and column 2 is TRUE, bubble BC.
If column 1 is FALSE and column 2 is FALSE, bubble BD.
Column 1
7.
CN is a base
BECAUSE
Column 2
it cannot donate an H+.
8.
An aqueous solution of potassium chloride
is a non-electrolyte
BECAUSE
the salt dissolves completely in solution.
9.
Ammonia will turn green/blue in red
cabbage juice
BECAUSE
its conjugate acid is NH4+.
−
SECTION 3: MULTIPLE CHOICE. Select the best answer choice for each question. (1 point each)
10. The solution shown to the right
can be considered
(A) Unsaturated
(B) Saturated
(C) Supersaturated
(D) It cannot be determined
14. Which one of these compounds is least soluble in
water?
(A) Hexane (non-polar)
(B) Nitrous acid
(C) Potassium carbonate
(D) Sucrose, C12H22O11 (polar)
11. According to the
solubility curve,
approximately
how many more
grams of
potassium nitrate
can be dissolved in
40 g water at 70°C
than at 40°C?
(A) 28 g
(B) 50 g
(C) 70 g
(D) 130 g
15. Which one of these compounds does not dissolve
in water?
(A) Ammonium phosphate
(B) Calcium carbonate
(C) Potassium chromate
(D) Zinc nitrate
12. Beaker A contains a saturated solution of NaCl
dissolved in 50 g water, while Beaker B contains a
saturated solution of NaCl in 100 g water. If
solutions for both beakers are at the same
temperature, which of the following is greater in
Beaker B than in Beaker A?
I. The ratio of the mass of dissolved NaCl to
the mass of water.
II. The mass of solute particles.
III. The molar mass of water.
(A) I only.
(B) II only.
(C) II and III only.
(D) I, II, and III.
13. In which of these conditions is CO2 LEAST
soluble in water?
(A) Temperature = 10°C
Pressure = 1.0 atm
(B) Temperature = 10°C
Pressure = 4.0 atm
(C) Temperature = 50°C
Pressure = 1.0 atm
(D) Temperature = 50°C
Pressure = 4.0 atm
16. What is the concentration of a solution made by
dissolving 12 grams NaOH in enough water to
make 0.50 L of solution?
Molar mass of NaOH = 40 g/mole
(A) 0.60 M
(B) 0.30 M
(C) 1.2 M
(D) 6.0 M
17. List the following solutions with an unknown
solute in increasing concentration.
X: 0.100 g solute in a 500 mL solution
Y: 0.100 g solute in a 250 mL solution
Z: 0.200 g solute in a 250 mL solution
(A) X < Y < Z
(B) X < Z < Y
(C) Y < X < Z
(D) Y < Z < X
18. A 100 mL sample of a solution with a
concentration of 5.00 M is diluted by adding 300
mL of distilled water. The new concentration will
be
(A) 1.25 M
(B) 1.66 M
(C) 15.0 M
(D) 20.0 M
19. If 50 mL of a 200 mL sample of 0.10 M sodium
chloride solution is spilled, what is the
concentration of the remaining solution?
(A) 0.025 M
(B) 0.075 M
(C) 0.10 M
(D) 0.20 M
20. Which of the following substances is a base?
(A) Ca(OH)2
(B) C2H5OH
(C) H2SO4
(D) HC2H3O2
21. A property of acids is that they
(A) feel slippery.
(B) neutralize water.
(C) taste bitter.
(D) taste sour.
22. According to Svante Arrhenius, acids are
substances that
(A) decrease the [H+]
(B) decrease the [OH–]
(C) increase the [H+]
(D) increase the [OH–]
23. Each of the following can describe an aqueous
solution with a strong electrolyte EXCEPT:
(A) The solute dissociates completely into ions.
(B) The solute is a covalent compound
(C) The solute is a strong acid.
(D) The solution contains a large amount of ions.
24. A substance that turns cabbage juice blue and only
slightly lights up a light bulb is a:
(A) strong acid
(B) strong base
(C) weak acid
(D) weak base
25. A solution has an [H+] = 1 × 10–4 M. What is the
[OH–]?
(A) 1 × 10–14 M
(B) 1 × 10–10 M
(C) 1 × 10–4 M
(D) 1 × 10–3 M
26. What is the hydrogen ion concentration, [H+], of a
solution in which the pOH is 9?
(A) 1 × 10–5 M
(B) 5 × 10–1 M
(C) 5 × 102 M
(D) 1 × 105 M
27. Which of the following solutions may have a pH =
8.0?
(A) Ammonia
(B) Pool acid
(C) Rubbing alcohol
(D) Vinegar
28. In the reaction below, which is the conjugate acid?
CH3NH3+ + OH−  CH3NH2 + H2O
(A) CH3NH3+
(B) OH−
(C) CH3NH2
(D) H2O
29. Which is the following is NOT a correct conjugate
acid-base pair?
(A) CH3COOH / CH3COO−
(B) H2CO3 / HCO3−
(C) H3O+ / OH−
(D) NH4+ / NH3
30. Which of the following solutions is expected to
have the lowest pH?
(A) 0.100 M HNO2
Ka = 4.0 × 10−4
(B) 0.100 M HC2H3O2
Ka = 1.8 × 10−5
(C) 0.100 M HOCl
Ka = 3.5 × 10−8
(D) 0.100 M HCN
Ka = 6.2 × 10−10
31. Which of the following is the correct expression
for Ka for the dissociation of weak base ammonia?
NH3 (aq) + H2O (ℓ)  NH4+ (aq) + OH− (aq)
[NH3]
(A) [NH +][OH−]
4
[NH3][H2O]
(B)
[NH4+][OH−]
[NH4+][OH−]
(C)
[NH3]
[NH4+][OH−]
(D) [NH ][H O]
3
2
SECTION 4: FREE RESPONSE. Show all your work to receive full credit.
32. Use the solubility curve to the right to answer the following questions.
(a) How many grams of potassium chloride can dissolve in 80 g water at
80°C? (2 points)
(b) How many grams of potassium nitrate will precipitate out when a
saturated solution with 600 g water at 80°C is cooled to 50°C? (4 pts)
33. What is the concentration of a solution when 0.400 mol KBr is used to prepare a 600 mL solution (4 points)
34. How many grams of Ca(NO3)2 is needed to prepare 120 mL of a 0.150 M solution? (4 points)
35. How many mL of a 6.0 M HCl solution are needed to prepare 120.0 mL of a 0.800 M solution? (4 points)
36. Complete the following table. No work is needed. (16 points total; 1 per box)
[H+]
[OH–]
pH
pOH
(a)
(b)
(c)
(d)
1.0 × 10–1 M
4.8 × 10−3 M
6.20
10.00
Acid/Base/Neutral
37. Find the pH of a 0.0150 M solution of HNO3. (6 points)
38. Given a 0.240 M solution of benzoic acid, HC7H6O2. The Ka of benzoic acid is 6.4 × 10−5.
(a) Write the dissociation equation for benzoic acid, and the expression for its Ka. (4 points)
(b) Find the pH and pOH of this solution. (6 points)
(c) Find the % dissociation of this solution. (2 points)
39. Find the concentration of all the ions in a 0.300 M solution of sodium phosphate. (4 points)
Solubility Rules for Salts
Always soluble:
 alkali ions, NH4+, NO3−, ClO3−, ClO4−, C2H3O2−, HCO3−
Generally soluble:
 Cl−, Br−, I−
Soluble except with Ag+, Pb2+, Hg22+
 F−
Soluble except with Pb2+, Ca2+, Ba2+, Sr2+, Mg2+
 SO42−
Soluble except with Pb2+, Ca2+, Ba2+, Sr2+
Generally insoluble:
 O2−, OH−
Insoluble except with Ca2+, Ba2+, Sr2+,
alkali ions, NH4+
 CO32−, PO43−, S2−, SO32−, CrO42−, C2O42−
Insoluble except with alkali ions and NH4+
Strong Acids
HCl, HBr, HI, HNO3, H2SO4, HClO3,
HClO4, HIO4
Strong Bases
LiOH, NaOH, KOH, RbOH, CsOH,
Ca(OH)2, Sr(OH)2, Ba(OH)2
Gases that Form
 H2S (g)
 H2CO3 (aq)  CO2 (g) + H2O (ℓ)
 H2SO3 (aq)  SO2 (g) + H2O (ℓ)
 NH4OH (aq)  NH3 (g) + H2O (ℓ)