Semester Exam
Review Questions – Solution Set
1. If 3.00 liters of a 6.75 M solution of nitric acid are diluted until the new concentration is
only 2.04 M, what will be the final volume of this diluted solution?
V
2
= M
1
V
1
/ M
2
= (6.75 M)(3.00 L) / 2.04 M = 9.93 Liters
2. How many hours does it take for a 3.000-gram sample of Ho-166 to decay until
only 0.225 grams remains behind? The half-life of Ho-166 is 48.6 minutes . k = 0.693 / 48.6 min = 0.01426 min -1  ln (3.000 g / 0.225 g) = 0.01426 min -1 (t)
t = 181.6 min = 3.03 hours
3. What are the products of a neutralization reaction? H
2
O (main product!) and a salt
4. What is the empirical formula of a substance that is analyzed and found to contain
68.43% barium, 10.30% phosphorus, and 21.27% oxygen?
68.43 / 137.3 10.30 / 31.0 21.27 / 16.0
= 0.4984 moles = 0.332 moles = 1.33 moles
Divide all by 0.332  1.50 : 1.00 : 4.00  x 2  3 : 2 : 8  Ba
3
P
2
O
8
5. How many grams of barium hydroxide need to be added to 750.0 ml of water in order to
produce a 0.880 M solution of this base?
(0.7500 L)(0.880 mole / 1 L)(171.3 grams / mole) = 113 grams of Ba(OH)
2
6. What is the molarity of a solution if 1.35 grams of sodium perchlorate is added to enough
water to make 25.0 ml of solution?
[ (1.35 g / 122.5 g/mol) / 0.0250 L] = 0.441 M
7. What is the mass, in grams, of a single molecule of hydrosulfuric acid? H
2
S(aq)
( 34.1 g / mole) ( 1 mole / 6.02 x 10 23 ) = 5.66 x 10 -23 grams
8. A 30.0-liter sample of dinitrogen pentoxide contains how many grams of oxygen?
( 30.0 L)( 1 mole cpd. / 22.4 L)(5 mol O / 1 mol cpd.)(16.0 g O / 1 mol O)
= 107 grams of oxygen in N
2
O
5
9. What is the percentage of barium in a 2.000-gram sample of barium chromate? BaCrO
4
% Ba = (137.3 g / 253.3 g) x 100 = 54.20 %
10. What is the mass of exactly 13.50 liters of carbon monoxide gas at STP conditions?
(13.50 L)(1 mole / 22.4 L)(28.0 grams / 1 mol) = 16.9 grams of CO
11. What is the number of hydrogen atoms in 34.7 grams of phosphoric acid ? H
3
PO
4
(34.7 g cpd)(1 mol cpd/98.0 g cpd)(3 mol H / 1 mol cpd)(1.0 g H / 1 mol H) = 1.06 g H

12. If you had 3.00 moles of gold(III) carbonate, how many moles of pure metallic gold could
you get from this sample? Au
2
(CO
3
)
3
(3.00 mol cpd.)(2 mol Au / 1 mol cpd) = 6.00 moles of Au
13. How many total atoms are in exactly 1.000 milligram of sodium sulfate? Na
2
SO
4
(0.001000 g cpd)( 1 mol cpd / 142.1 g cpd)(7 mol atoms / 1 mol cpd)(Av # / 1 mol)
= 2.97 x 10 19 atoms total
14. How many ions (total) are there in 0.0250 moles of chromium(III) acetate ? Cr(C
2
H
3
O
2
)
3
(0.0250 mole cpd)( 4 mol ions / 1 mol cpd )(Av # / 1 mol) = 6.02 x 10 22 ions total
15. How many moles of metal can be recovered from 125 grams of strontium molybdate? SrMoO
4
Remember that both Sr & Mo are metals!
(125 g cpd)(1 mol cpd / 247.54 grams )2 mols metal / 1 mol cpd) = 1.01 mol
16. What is the energy of a photon from if its wavelength is 12.5 nanometers?
 E = hc /  = (6.626 x 10 -34 )3.00 x 10 17 nm) / 12.5 nm = 1.59 x 10 -17 joule
17. Give the electron configuration (using the noble gas core configuration) for
a neutral cadmium atom.
[Kr] 5s 2 4d 10 [Remember: as a check, the sum
total of superscripts should add up to equal the atomic number (the Z#)]
18. What is the mass, in kilograms, of an object that weighs 88.95 tons?
( 88.95 tons)(2000 lbs. / 1 ton)(0.4536 kg / 1 lb) = 8.070 x 10 4 kg
19. A line that measures 8.005 inches is how many millimeters long?
(8.005 inches)(2.54 cm / 1 in.)( 10 mm / 1 cm) = 204.5 mm
Name the following compounds:
20. iron(III) manganate Fe
2
(MnO
4
)
3
23.
carbonic acid H
2
CO
3(aq)
21. triphosphorus heptasulfide P
3
S
7
24. cadmium hypochlorite Cd(ClO)
2
22. hydrofluoric acid HF
(aq)
25. holmium sulfate Ho
2
(SO
4
)
3

For the next set, predict the type of reaction and tell whether or not it will go as written:
26. D.R
FeBr
2
+ KCl -------------> KBr + FeCl
2
No – no evidence of a reaction – everything is soluble
27. Syn . SO
2
+ K
2
O -------------> K
2
SO
3
Yes – correct products
28. Dec . FeCO
3
-------------> FeC + O
2
No – wrong products  should be Fe
2
O
3
+ CO
2
29. D.R
AgBr + CsI -------------> CsBr + AgI
No – AgBr is not soluble
30. S.R.
Mg + H
3
PO
4
----------> Mg
3
(PO
4
)
2
+ H
2
Yes – Mg is more active than H
Complete the following reactions:
31. diphosphorus pentoxide plus water (synthesis reaction of an acidic anhydride w/ water)
P
2
O
5
+ 3 H
2
O  2 H
3
PO
4
32. aqueous solutions of sodium sulfide and nickel(II) acetate are mixed (D.R. – ppt. reaction)
Na
2
S + Ni(C
2
H
3
O
2
)
2
 NiS + 2 NaC
2
H
3
O
2
Not asked for, but need to know: Net ionic: S -2 + Ni +2  NiS (ppt.)
33. solution of nitric acid and barium carbonate are mixed (D.R. – acid-base reaction)
2 HNO
3
+ BaCO
3
 Ba(NO
3
)
2
+ H
2
O + CO
2
When 180.0 ml of a 3.00 M solution of nickel (II) sulfate are mixed with 290.0 ml
of a 2.00 M solution of silver nitrate, 45.0 grams of a white precipitate were recovered.
Answer the following questions based on this information.
34. Write the balanced equation for this reaction.
NiSO
4
+ 2 AgNO
3
 Ag
2
SO
4
(ppt.) + 2 Ni(NO
3
)
2
(aq)
35. How many moles of each reactant were there?
moles of NiSO
4
= (0.1800 L)(3.00 M) = 0.540 mole
moles of AgNO
3
= (0.2900 L)(2.00 M) = 0.580 mol
36. What is the limiting reagent? AgNO
3
Because of the 1 : 2 ratio, for every 0.540 mol of NiSO
4
, you will need 1.08 mol AgNO
3
Since there are only 0.580 moles of AgNO
3
, it is the LR. (you don’t have enough!)
37. How many moles of excess reagent were left unreacted?
For 0.580 moles, then only 0.290 moles of NiSO
4
are needed
0.540 – 0.290 = 0.250 mole xcs

38. What is the precipitate? A g
2
SO
4
39. How many grams of precipitate should have been formed theoretically?
(0.580 mol LR)(1 mol ppt / 2 mol LR)(311.9 g ppt / 1 mol ppt) =
90.45 g
40. What is the percent yield for this reaction?
% yield = actual / theoretical x 100 = 45.0 g / 90.45 x 100 = 49.8%
Write formulas for the following compounds:
45. AuBr
3 gold(III) bromide 47. Sb(IO
3
)
3 antimony (III) iodate
46. H
2
SO
3
(aq) sulfurous acid 48. (NH
4
)
2
Cr
2
O
7 ammonium dichromate
49. -60.0
o
C corresponds to what temperature on the Kelvin scale? o K = C + 273 = 213 K
50. List two physical extensive properties.
Volume, mass, heat capacity, length, surface area
51. List two physical intensive properties.
Density, specific heat, heat of fusion, heat of vaporization, boiling point,
Malleability, luster, electrical conductivity, viscosity
====================================================================
52. What is the [OH
-1
] of an acidic solution if the pH = 2.22?
pOH = 14 – 2.22 = 11.78  [OH -1 ] = 10 -11.78
= 1.7 x 10 -12 M
53. What is the percent ionization of a weak base if a 0.175 M solution has a pH of 11.93?
A) 0.450%; B) 10.4%; C) 4.87%; D) 2.38%; E) 4.28 x 10
-3
%.
If pH = 11.93  pOH = 2.07  [OH -1 ] = 0.0085 M
0.0085 / 0.175 x 100 = 4.86% hybridization
54. What is the geometric shape of OF
of PCl
of SeF
2
4
3
? 2 / 2 = bent sp
-2
? 3 / 1 = trig. pyramid sp
3
? 4 / 2 = square planar sp
3
of CH
4
? 4/ 0 = tetrahedral sp 3
3 d 2
55. What is the molecular weight of a gas if 4.90 grams is contained in a 6.00-liter vessel
at 550.0 mm Hg pressure and 220.0
o
C?
MWt. = gRT / PV = [(4.90 g)(62.4 mm/mole-K)(493 K)] /[(550.0 mm](6.00 L)]
MWt. = 45.7 g/mole

56. If the density of propanol is 0.93 g/ml, what is the molality of a solution in which 100.0 grams
of sucrose (MW = 342 g/mole) is dissolved in 1800.0 ml of propanol (MW = 60.0 g/mole)? m = moles solute / kg solvent
(1800.0 mL )(0.93 g/mL) = 1674 g solvent = 1.7 kg
Then m = [(100.0 g / 342 g/mol)] / 1.7 kg = 0.17 m
57. Of the following compounds, which would have the strongest ionic bonding,
based on lattice energy?
A) NaCl; B) NaBr; C) CsBr; D) MgCl
2
;
E) VBr
3
 E = lattice energy = kQ
1
Q
2
/ r VBr
3
has the greatest charge / size ratio
58. In a reaction, manganese dioxide (MnO
2
) changes to give a permanganate ion.
Was the substance: A) oxidized; B) reduced; C) neutralized.
“oxidized” is to lose electrons;
the charge on Mn went from +4 to +7 (lost electrons)
60. An aqueous solution boils at 106.2
o
C when 90.0 grams of an unknown solute is dissolved
in 75 ml of water. What is the molecular weight of the solute? K b
= 0.512 o
C/m.
MWt = (g x k b
)/ (  t x kg) = (90.0 g)(0.512) / (6.2)(0.075 kg) = 99 g/mole
62. Which of these molecules would be expected to show a dipole moment (be polar)?
A) SO
2
; B) CH
3
F; C) AsF
3
;
D) CCl
4
; E) OF
3
.
[Need an electronegativity difference (  EN) greater than 0.5 and also need the molecular
shape to allow for one “end” of the molecule to have a different charge than the other “end”.
64. Give an example of a material that may be considered to be amorphous. glass
65. Atoms of
24
Mg
12
will most readily unite by ionic bonding with atoms of the element having atomic number: A) 18; B) 3; C) 14; D) 13;
E) 34
Looking for a nonmetal that will have a negative charge, like Se -2 .
66. What is the term for the smallest portion of the crystal lattice that exhibits the pattern of the lattice structure?
Unit cell
67. In the reaction, NH
4
+1
+ H
2
O -----> NH
3
+ H
3
O
+1
, the water molecule serves as:
Acid Base Conj. Base Conj. Acid
A) a proton donor;
B) a proton acceptor; C) a weak base; D) an electrovalent compound.
68. What is the pH of a solution that has a hydronium ion [H
3
O
+1
] concentration of 0.00340 mole per liter? What would be the pOH of this solution?
pH = -log[H + ] = 2.468 pOH = 14 – pH = 11.532

69. How many moles of methane (MW = 16.0 g/mole) are there in a 20.00-liter container if the pressure is 1200.0 mm Hg and the temperature is measured to be -75.0
o
C?
PV = nRT  n = [(1200.0 mm)(20.00 L)] / [(62.4)(198 K)] =
1.94 moles
70. When a substance can act as either an acid or a base depending on the reaction in which it is involved, the substance is called:
A) amphoteric;
B) divalent; C) allotrophic; D) covalent; E) isomeric.
71. If an acid is said to be strong , this means:
A) it is highly corrosive; B) it is ionized completely in aqueous solution;
C) it has a sharp bitter odor; D) it holds together in water as a molecule rather than as ions.
72. Which of the following does not affect the rate of a reaction?
A) temperature; B) concentration of the reactants; C) time; D) catalyst; E) nature of reactants.
“time” would be the independent variable.
Xe-137 has a half-life of 15.0 days. Use this information to answer the next set of questions.
73. What is the specific rate constant (k) for this radioactive material? k = 0.693 / 15.0 days = 0.0462 day -1
74. If a student starts with 20.00 grams of the sample, how many days will be required before
only 12.5% of the original sample remains?
12.5% = 1/8 = 3 half-lives = 45.0 days
75. Starting with a 56.0-gram sample, how many grams remain after exactly 60.0 days?
60.0 / 15.0 = 4 half-lives = 56.0(0.50) 4 = 3.50 grams
Give the shape, type of hybridization, and bond angle for the following:
76. xenon tetrachloride 79. ethyne – C
2
H
2
8 + 28 = 36 = 4 / 2 (both carbons count as “central”)
= square planar, sp 3 d 2 , 90 o = linear, sp, 180 o
77. phosphorus pentachloride 80. sulfur tetrafluoride
5 + 35 = 40 = 5 / 0 6 + 28 = 34 = 4 / 1
= trig. bipyramid, sp 3 d, 90 o & 120 o = seesaw, sp 3 d, 90 o & 120 o
78. carbonate ion 81. hydrogen sulfide gas
4 + 18 + 2 = 24 = 3 / 0 2 + 6 = 8 = 2 / 2
= trig. planar, sp 2 , 120 o = bent, sp 3 , < 109.5
o

82. What is the molal freezing point constant for an organic solvent given the following information: when 4.00 grams of a nonvolatile, nonelectrolyte (MW = 255 g/mole) are added to 150.0 grams of the organic solvent the freezing point of the resulting solution is measured at 34.5
o
C.
The pure solvent freezes at 38.2
o
C.
 t = k f
x m  k f
= (38.2 – 34.5) / [(4.00 g / 255 g/mol) / 0.1500 kg ]
k f
= 3.7 / 0.1046 m = 35.4 o C / m
Classify the following solids: (ionic, covalent network, atomic/molecular, or metallic
83. magnesium chloride 85. ammonia 87. silicon dioxide
ionic molecular covalent network
84. methane 86. pure copper 88. glucose
molecular metallic molecular
89. What is the molecular weight of an unknown gas is its rate of effusion is 34.5 ml/sec while
oxygen's rate of effusion is 25.1 ml/sec?
Rate X 34.5 32.0 g/mol
--------- = ------ = -------------  X = 16.9
Rate O
2
25.1 X
[Remember to check – the “lighter” gas should have a faster rate of effusion.]
Tell what the predominant type of intermolecular force exists between:
90. water and ethyl alcohol 92. oil and vinegar
hydrogen van der Waals
91. potassium nitrate dissolved in water 93. an alloy of brass composed of copper and zinc
Ion - dipole metallic
94. What type of hybridization is exhibited by the sulfur trioxide molecule? 3 / 0 sp 2
95. What type of hybridization exists in the phosphorus trifluoride molecule?
3 / 1 sp 3
96. If 5.00 liters of gas that is confined in a movable piston at STP has the temperature raised to 500 o
C and the pressure decreased to 35.0 kPa, what will be the new volume of this gas?
V
1
P
1
T
2
(5.00 L)(101.3 kPa) (773 K)
V
2
= --------- x ------- = ------------------------------------- = 41.0 Liters
T
1
P
2
(273 K) (35.0 kPa)

97. What is the specific heat of a metal given the following information:
166.0 grams of the metal, when dropped into 45.0 grams of distilled water, has its
temperature lowered by 45.5
o
. The water temperature rises by 13.4
o
Heat lost = - Heat gained  mC  t = mC
(45.0 grams)(4.184 J / go
 t
C)(13.4
o )
C(metal) = -------------------------------------------- = 0.334 J / go C
(166.0 grams)(45.5
o )
98. What is the term for the property of colloids that diffracts light? Tyndall effect
99. Which of these molecules would be expected to be polar?
A) O
2
; B) HCl; C) CO
2
; D) CCl
4
; E) none of these.
102. If equal moles of HCl and KOH are dissolved in 1.0-liter of water, what would be the pH of the final solution? A) 1.0; B) 14; C) 7.0; D) 0; E) can't be determined from the info given.
103. How many milliliters of 0.20 M NaOH are needed to neutralize 12.5 ml of conc. HCl (12.0 M)?
A) 750 ml; B) 800 ml; C) 960 ml; D) 1200 ml; E) 1920 ml.
V
B
= (M
A
x V
A
) / M
B
= (12.0 M)(12.5 mL) / (0.20 M) = 750 mL
104. How do you distinguish between a “qualitative” and a “quantitative” piece of data?
Give an example of each.
“qualitative” does not depend on an amount – a measurable quantity
“quantitative” is a measurable amount
Qual – color, smell, Quant = mass, volume
105. What is the identity of the alpha particle, the beta particle, and the gamma ray?
What are the charges of these particles? The masses? Which penetrates the most?
alpha (

) = nucleus of the helium atom = 4 He
2
has a +2 charge;
slowest moving, most damaging, least penetrating
can be stopped by a sheet of paper (or your skin)
beta (

) = high-speed electron; has a -1 charge
can be stopped by a sheet of aluminum foil
gamma (

) = pure energy; no charge (or mass)
= most damaging, highest penetration, fastest moving
can only be stopped by 6” of Pb or feet of concrete
106. What is the difference between an independent and a dependent variable in an experiment?
In the acid-base titration, which was which?
“independent” variable is the one that you change in order to see what impact it has
“dependent” is the variable that is a function of the independent variable
When you titrated the acid solution with a standardized base, the volume of the
Acid was dependent on the volume (and the molarity) of the base solution.
107. How does a catalyst affect the activation energy of a reaction?
It provides an alternate pathway that requires less energy. [Could also be said
that it lowers the activation energy (on some standardized tests.)]

Using the following key to answer the questions about the following reaction:
( all reactants and products are gases )
A) increases; B) decreases; C) no change; D) cannot determine;
E) shifts right; F) shifts left
2 A + 3 B <=========> C + 2 D  H = -35.4 kcal Temperature is 565 K
108. Increasing the concentration of C would have what effect on the concentration of D?
B – since rxn shifts left (away from C)
109. Increasing the temperature would have what effect on the value of K
C
?
B – since rxn shifts left (exothermic)
110. Putting a solid catalyst (promoter) into the reaction vessel would have what effect
on the position of the equilibrium?
C – doesn’t change either position or the value of K
111. Moving the reaction from a 1.0-liter vessel into a 2.0-liter vessel would cause the reaction mixture to shift which way?
B – since rxn shifts left (towards the larger number of moles of gas)
112. Removing some reactant B from the reaction would have what effect on [D]?
B – since rxn shifts left (to make up for the lost “B”)
113. Increasing the pressure on the reaction would have what effect on the position of the equilibrium?
A – since rxn shifts right (away from the larger number of moles of gas)
114. A decrease in temperature will have what effect on the number of moles of A,
if pressure and volume are kept constant?
B – since rxn shifts right (exothermic)
=========================================================================
Consider the following reaction: All substances are gases :  H = -12.3 kJ
A + 2 B <==========> C + 2 D Keq = 4.2 x 10
3
at 25 o
C
115. When the pressure on the equilibrium reaction is tripled, what will happen?
A) reaction will shift to the right with no change of K;
B) reaction will shift to the left with no change of K;
C) reaction will shift to the right with a change of K;
D) reaction will shift to the left with a change of K;
E) the reaction will not shift and K will not change.  n gases = 0
116. The reaction: 2 A + 3 B  2 C + D (all gases at 1.00 atm. & 298 K) has an equilibrium constant value (K
C
) of 14.5. If the equilibrium concentrations are as follows, what is the [C]? [A] = 3.00 M, [B] = 2.50 M, and [D] = 1.75 M
[C] 2 [D] [C] 2 [1.75]
K = 14.5 = ----------- = ---------------  [C] 2 = 1165 
[A] 2 [B] 3 [3.00] 2 [2.50] 3
[C] = 34.1 M