Download 1. When 10.0 g NH4Cl (formula weight, 53.49 g mol ) is dissolved in

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CHEM 120 – Test #2 (Sample)
1.
When 10.0 g NH4Cl (formula weight, 53.49 g mol−1) is dissolved in water in a
calorimeter, the temperature decreases from 25.50oC to 24.87oC. If the heat capacity of
the calorimeter (and its contents) is 4.51 kJ oC−1, what is the molar heat of solution of
NH4Cl?
A. 38.3 kJ mol−1
B. 7.47 kJ mol−1
C. 0.531 kJ mol−1
D. 71.6 kJ mol−1
E. 15.2 kJ mol−1
2.
Given the following thermochemical equations,
N2(g)
+
(3/2) O2(g)
N2(g)
+
O2(g)
→
(1/2) N2(g) + O2(g)
what is ∆Hrxn for
A. −207.1 kJ
B. −39.7 kJ
C. 24.3 kJ
D. 39.7 kJ
E. 207.1 kJ
N2O3(g)
→
N2O3(g)
∆Hrxn = 180.4 kJ
2 NO(g)
→
→
NO2(g)
NO(g)
∆Hrxn = 83.7 kJ
+
∆Hrxn = 33.2 kJ
NO2(g)?
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CHEM 120 – Test #2 (Sample)
3.
Given that ∆H o = +542.2 kJ for the reaction
2 HF(g) → H2(g) + F2(g),
what is ∆H of for HF(g)?
A. −542.2 kJ mol−1
B. −271.2 kJ mol−1
C. −135.6 kJ mol−1
D. +135.6 kJ mol−1
E. +271.2 kJ mol−1
4.
Given the standard enthalpies of formation
CH4(g),
−74.8 kJ mol−1
H2O(g),
−242 kJ mol−1
CO2(g),
−394 kJ mol−1
O3(g),
+143 kJ mol−1
what is ∆H o for the reaction
3 CH4(g) + 4 O3(g) → 3 CO2(g) + 6 H2O(g) ?
A. −2982 kJ
B. −4164 kJ
C. −704 kJ
D. +704 kJ
E. +2982 kJ
5.
Which of the following statements are true?
(I)
Ultraviolet light has more energy per photon than infrared radiation.
(II)
The wavelength of blue light is longer than that of red light.
(III) X-rays travel much faster than radio waves.
(IV) The energy of a photon is inversely proportional to its frequency.
A. (I) only
B. (I) and (II)
C. (II) and (IV)
D. (II), (III), and (IV)
E. (I) and (IV)
CHEM 120 – Test #2 (Sample)
6.
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Which of the following combinations of n, l, and ml are appropriate for an electron in a
hydrogen atom?
(I)
(II)
(III)
(IV)
n=1
n=4
n=3
n=1
l=0
l=2
l=3
l=0
ml = 0
ml = 2
ml = −3
ml = (1/2)
A. (I) only
B. (I) and (II)
C. (I), (II), and (III)
D. (II) and (IV)
E. (I) and (III)
7.
A ground state H atom absorbs a single photon of radiation of wavelength 121.6 nm.
After the atom absorbs the photon, the principal quantum number of the electron is
A. 2
B. 3
C. 4
D. 5
E. greater than 5
8.
What is the ground state electron configuration for iron (Z = 26) ?
A. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 8
B. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10
C. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6
D. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 4p 6
E. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6
CHEM 120 – Test #2 (Sample)
9.
One of the valence electrons in a ground state atom has the quantum numbers
n = 3,
l = 1,
ml = 0,
ms = −(1/2). The atom could be
A. sulfur
B. potassium
C. calcium
D. bromine
E. arsenic
10.
Which of the following atoms has the highest first ionization energy?
A. P
B. Mg
C. S
D. Al
E. Si
11.
Which of the following atoms has the largest radius?
A. K
B. Al
C. S
D. As
E. Br
12.
How many unpaired electrons are there in a ground-state Ni atom ?
A. zero
B. one
C. two
D. three
E. four
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CHEM 120 – Test #2 (Sample)
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Answers
1
E
2
D
3. B
4. A
5. A
6. B
7. A
8. C
9. A
10. A
11. A
12. C
The final temperature should have been given as 24.87oC. It has been corrected
in this version of the sample test.
The cofficient of O2 in the first chemical equation should have been (3/2). This
has been corrected in this version of the sample test.