EXAM # 3
Activity Series of Metals in Aqueous Solution
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CHEM 1405 Exam #3
(Chapters 7, 8, 9)
Name: _____________________________________
Score:
Part I- (3 points each) - Please write your correct answer next to each question number,
DO NOT CIRCLE
_____ 1. Which of these represent a strong electrolyte in aqueous solution?
A. N
2
B. C
6
H
12
O
6
C. KBr D. KI E. C and D
_____ 2. What is the oxidation number on N and P in KNO
2
and PO
43-
respectively?
A. +3,+5 B. +5,+3 C. +2, +3 D. +4, -5 E. +3, -5
_____ 3. Which reactions shown below will not yield a solid precipitate?
A. AgNO
3
+ KBr B. Pb(NO
3
)
2
+ KCl C. BaBr
2
+ Na
2
SO
4
D. NaNO
3
+ NH
4
Cl E. CaI
2
+ (NH
4
)
2
CO
3
_____ 4. How many grams of H
2
SO
4
are in 800 mL of a 0.20 M sulfuric acid solution?
A. 0.24 g B. 16 g C. 2.4 g D. 0.16 g E. 38 g
_____ 5. Considering the following reaction Cu + 2 AgNO
3
 Cu (NO
3
)
2
+ 2 Ag, which is correct?
A. Cu is oxidized B. Ag + is reduced C. Cu is reducing agent
D. Ag + is reducing agent E. A,B, C only
_____ 6. If 20 mL of 0.12 M solution of Ca(OH)
2 is neutralizes to 48 mL of HBr, What is the
concentration of the HBr?
A. 0.02 M B. 0.50 M C.0.10 M
_____ 7. Which of the following is a correct statement?
A. Hydrofluoric acid is a strong acid.
D. 0.03 M E. 0.005 M
B. The strength of an acid or base refers to its relative concentration.
C. The equivalence point in an acid-base titration occurs when the volumes of the acid
and base is equivalent.
D. Acid-base reactions lead to the direct formation of a precipitate.
E. Acetic acid is a weak acid.
_____ 8. All of the following are weak acids except
A. HCNO B. HBr C. HF D. HNO
2
E. HCN
2

_____ 9. How many grams of NaCl are contained in 350.ml of a 0.250 M solution of sodium chloride?
A. 41.7g B. 5.12g C. 14.6g D. 87.5g E. None of these
_____10. The interaction Zn + H
2
SO
4
→ ZnSO
4
+ H
2
which element (if any) is oxidized?
A. zinc B. hydrogen C. sulfur D. oxygen E. None of these
_____11. In which of the following does nitrogen have an oxidation state of +4?
A. HNO
3
B. NO
2
C. N
2
O D. NH
4
Cl E. NaNO
2
_____12. In the balanced molecular equation for the neutralization of sodium hydroxide with sulfuric acid, the
products are:
A. NaSO
4
+ H
2
O B. NaSO
3
+ 2H
2
O C. 2NaSO
4
+ H
2
O
D. Na
2
+2 H
2
O E. Na
2
SO
4
+ 2H
2
O
_____13. What volume of 18.0 M sulfuric acid must be used to prepare15.5L of 0.195 M H
2
SO
4
?
A. 168 ml B. 0.336L C. 92.3 ml D. 226 ml E. None of these
_____14. When a radioactive atom undergoes spontaneous decomposition it can release
A.
Electron
B.
Proton
C.
Neutron
D.
All of the above
_____15. A commonly used nuclear fuel
A. Potassium
B.
Beryllium
C.
Carbon
D.
Uranium
_____16. The combining of two lighter atomic nuclei to form a heavier atomic nucleus is
called
A.
Radioactive decay
B.
Nuclear fission
C.
Nuclear fusion
D.
All of the above
_____17. The REM is a unit of exposure to radiation that is a measure of the
A.
Risk of getting cancer from radiation exposure
C.
Half-life of an isotope
B.
Numbers of decays per minute of an unstable nucleus
D.
Biological damage to tissue
_____18. Some forms of electromagnetic radiation include
A.
X-rays
B.
Light
C.
Radio waves
D.
All of the above
_____19. Gamma radiation is a
A. Particle
B.
Type of electromagnetic radiation
C.
Particulate isotope
D.
None of the above
_____20. Ionizing radiation affects ___ which can lead to mutations
A.
Cell membrane
B.
Cell wall
C.
DNA
D.
None of the above
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PART II- ( 8 points each) Please show all your work.
21. Sodium sulfate reacts with barium iodide. Write a complete molecular, ionic, and net ionic
equation for the reaction and identify the spectator ions.
22. How many milliliters of 0.1M HNO
3
will react completely with 15.31 mL of 0.03M Ca(OH)
2
?
23. A 10 mL acetic acid with a density of 1.04 g/ml was added to 60 mL of water. (a) Calculate
the volume percent of the solution. (b) Calculate the mass of the solute. (c) Calculate the
weight percent of the solution. (d) Calculate the molarity of the solution
24.
A solution was prepared by dissolving 6.00 g acetic acid in 500.00 mL distilled water.
Accidentally, a student in your lab, added 5.00 mL of 10 M sodium hydroxide to the
500.00 mL acetic acid solution you prepared earlier. a.
Calculate the concentration of sodium hydroxide. b.
Calculate the concentration of the acetic acid. c.
Write and balance the equation of the reaction.
25.
Match each reaction on the left with the type of equilibrium that it represents on the right, below:
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1.
Fe 3+ + SCN _  FeSCN 2 a) Acid-base
2.
Ag
2
S  2Ag + + S 2- b) Solubility
3.
Hac  H + + Ac _ c) Oxidation/reduction
4.
Cr
2
O
72-
+ 6 Fe 3+ + 14H +  Cr 3+ +6 Fe 3+ + 7H
2
O d) Complexation
Bonus Question ( 10 points) - Please show all your work. (answer only one)
26.
Explian why water is considered one of the best and most universal solvent.
Some of the facts water is considered one of the best and most universal solvent are water has a pH of 7 and this makes water neutral, water is slightly polar that appears momentarily and this makes water to dissolve most compounds, water is present in all living organisms and water is the main chemical that is needed for life on earth and anywhere.
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PART II- ( 8 points each) Please show all your work.
1.e 2.a 3.d 4.b 5.e 6.c 7.c 8.b 9.b 10.a 11.b 12.e 13.a 14.d 15.d 16.c 17.d 18.d 19.b 20.c
21. Molecular Equation: Na
2
SO
4
(aq) + BaI
2
(aq) = NaI (aq) + BaSO
4
(s)
Ionic Equation: 2Na + (aq) + SO
42-
(aq) + Ba + (aq)+ 2I (aq) = 2Na + (aq) + 2I (aq) +BaSO
4
(s)
Net Ionic Equation: Ba + (aq) + SO
42-
(aq) = BaSO
4
(s)
Spectator Ions: Na + (aq) + I (aq)
22. 2HNO
3
+ Ca(OH)
2
= Ca(NO
3
)
2
+ 2H
2
O is a balanced equation
Using M b
x V b
= b where “b” is ratio of base (= 1) to ratio of acid “a” (= 2)
M a
x V a
a
0.03 M x 15.31 mL = 1, V a
= 9.186 mL
0.1M x V a
2
23.
Identify the solute based on the given data. The solute is acetic acid.
The total volume of the solution is 60 mL + 10 mL. a.
Volume percent of solution = 10 mL/70 mL x 100% = 14.3% b.
Gram solute = Density x Volume = 1.04 g/mL x 10 mL = 10.4 g c.
Weight percent of solution =10.4 g/(60 + 10.4) g x 100% = 14.7% d.
Molarity (M) = Gram solute/Formula weight/Liter of solution
= 10.4 g/60 g/0.070 L = 0.00248 M = 0.003 M
24.
5 mL spilled in 500 mL acetic acid a. C
1
V
1
= C
2
V
2
, C
1
= 5mL x 10 M/505 mL = 0.099 M of NaOH b. Concentration of Acetic acid (C
2
) = 6.00 g/60 g/0.505 = 0.198 M c. NaOH + CH
3
CO
2
H <==> NaCH
3
CO
2
+ H
2
O
25. 1. Complexation 2. Solubility 3. Acid-base 4. Oxidation/reduction
26. Explian why water is considered one of the best and most universal solvent.
Some of the facts water is considered one of the best and most universal solvent are
water has a pH of 7 and this makes water neutral, water is slightly polar that
appears momentarily and this makes water to dissolve most compounds, water is
present in all living organisms and water is the main chemical that is needed for life
on earth and anywhere.
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