CHEM 101 2nd Majer (Term 112)

Name: __________________________ Date: _____________
1. Calculate the work, and determine whether it is done by the system or on the system
when 45 J of heat is released and the internal energy increased by 313 J.
A)
B)
C)
D)
E)
+358 J, work done on the system
+268 J, work done on the system
+358 J, work done by the system
+268 J, work done by the system
−268 J, work done by the system
2. Consider this reaction
∆H = –92.6 kJ/mol
N 2 (g) + 3 H 2 (g)  2 NH 3 (g)
When 5.00 g of N 2 react with excess mol of H 2 to form NH 3 at 1 atm and a certain
temperature, there is a decrease in volume equal to 49 L. Calculate ∆U for this reaction.
(1 L.atm = 101.3 J).
A)
B)
C)
D)
E)
-11.6 kJ
-97.6 kJ
+97.6 kJ
+43.6 kJ
-14.6 kJ
3. A 22.0 g piece of metal is heated to 100.0°C and placed in 75.0 g H 2 O at 25°C. If the
final temperature of the metal and water is 27.8°C, what is the specific heat of the metal
in J/g·°C?
A)
B)
C)
D)
E)
0.55
0.16
0.038
12
1.6
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4. Which one of the following reaction corresponds to the standard enthalpy of formation
(ΔH f °) for CuSO 4 (s)?
A)
B)
C)
D)
E)
Cu(s) + S(s) + 2O 2 (g) CuSO 4 (s)
Cu2+(aq) + SO 4 2-(aq)  CuSO 4 (s)
CuO(s) + SO 3 (g) CuSO 4 (s)
CuS(s) + 2O 2 (g)CuSO 4 (s)
Cu (s) + SO 2 (g) + O 2 (g)CuSO 4 (s)
5. A quantity of 3.00 x 102 mL of 0.950 M HCl is mixed with 3.00 x 102 mL of 0.220 M
Ba(OH) 2 in a constant-pressure calorimeter. The initial temperature of both acid and
base solutions is the same at 21.0° C. What is the final temperature of the mixed
solutions?
For the process: H+ (aq) + OH-(aq) → H 2 O(l) ΔH = -56.2 kJ/mol. Assume that the
specific heat and density of solutions are the same as those of pure water.
A)
B)
C)
D)
E)
24.0° C
18.2° C
52.3° C
25.6° C
36.8° C
6. What is maximum number of electrons that can have the following set of quantum
numbers?
n = 4 and m l = -1
A)
B)
C)
D)
E)
6
8
0
2
14
7. What is the energy of a one mole of photons of microwave radiation with a wavelength 0.122
m?
A)
B)
C)
D)
E)
0.980 J/mol
1.63 x 10-24 J/mol
2.71 x 10-48 J/mol
1.62 x 10-19 J/mol
8.04 J/mol
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8. How many electrons are there in all the p orbitals of a vanadium atom (V)?
A)
B)
C)
D)
E)
12
6
3
5
10
9. Calculate the frequency of the light emitted by a hydrogen atom during a transition of its
electron from the n = 4 to the n = 1 principal energy level.
A)
B)
C)
D)
E)
3.08 × 1015 s-1
1.03 × 108 s-1
2.06 × 1014 s-1
1.35 × 10-51 s-1
8.22 × 1014 s-1
10. Calculate the wavelength for a neon atom (Ne) moving with a velocity of 2.00 x 105
m/s.
A)
B)
C)
D)
E)
9.89 x 10-5 nm
1.89 x 10-7 nm
7.15 x 10-9 nm
9.75 x 1012 m
2.08 x 10-4 nm
11. Which of these ground-state ions has at least one unpaired electron?
A) Sc2+
B) V5+
C) Mg2+
D) P3E) S2-
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An element has an electron configuration of 1s22s22p63s2. Which electrons
experience the greatest effective nuclear charge, and which experience the most
shielding, respectively?
12.
Greatest effective : most shielding
nuclear charge
A)
B)
C)
D)
E)
1s2 electrons
1s2 electrons
2s2 electrons
3s2 electrons
3s2 electrons
:
:
:
:
:
3s2 electrons
2s2 electrons
3s2 electrons
2s2 electrons
2p6 electrons
13. The similar chemical properties of the elements in a given group in the periodic table is
explained by the fact that atoms of these elements have:
A)
B)
C)
D)
E)
the same number of electrons in the valence shell.
similar nuclear structures.
the same number of protons.
the same number of isotopes.
the same number of electrons.
14. How many bonding electrons are there around the central Cl atom in a ClO 3 - anion in its
"most preferable" Lewis structure?
A)
B)
C)
D)
E)
10
8
12
6
5
15. The first ionization energy for S is lower than the first ionization energy for P because:
A)
B)
C)
D)
E)
S has a stronger electron-electron repulsion in the p orbital.
Hund's rule is violated.
P is more electronegative than S.
P atom is bigger in size than S atom.
S has more unpaired electrons than P.
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16. Calculate the lattice energy of CaCl 2 using the following data.
IE 1( Ca) = 590 kJ/mol,
IE 2 (Ca) = 1145 kJ/mol,
∆H f [Ca(g)]=179.3 kJ/mol,
∆H f [Cl(g)] = 121.7 kJ/mol,
∆H f [CaCl 2 (s)] = −794.6 kJ/mol,
EA(Cl) = 349 kJ/mol,
A)
B)
C)
D)
E)
2254
1287
1254
1145
2154
17. Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.
A)
B)
C)
D)
E)
S > As > Ca > Rb
S > As > Rb > Ca
As > S > Rb > Ca
As > S > Ca > Rb
Ca > S > As > Rb
18. Estimate the enthalpy of combustion reaction of methane (CH 4 )?
(Note: You need to write and balance the reaction between CH 4 and O 2 ).
Given:
A)
B)
C)
D)
E)
C-H 414 kJ/mol;
C=O 799 kJ/mol; and
O=O 498.7 kJ/mol;
H-O 460. kJ/mol.
-785 kJ/mol
+785 kJ/mol
-370 kJ/mol
+370 kJ/mol
+550 kJ/mol
19. Which one of the following follows the octet rule?
A)
B)
C)
D)
E)
CO 2
NO 2
ClO 2
BF 3
SF 6
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20. In the following Lewis structure for ClO 3 F, chlorine has a formal charge of ____ and an
oxidation number of ____.
A)
B)
C)
D)
E)
1, 7
7, -1
1, 1
1, -1
7, -7
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Answer Key
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A
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A
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