Study Questions
Chem 101 LACC
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Electromagnetic radiation with a wavelength of 525 nm appears as green light to the human
eye. The energy of one photon of this light is __________ J.
A) 1.04 × 10-22
B) 2.64 ×
C) 1.04 × 10-31
D) 3.79 ×
E) 3.79 ×
2) Consider the molecule below. Determine the molecular geometry at each of the 2 labeled
carbons.
A) C1 = bent, C2 = trigonal planar
B) C1 = trigonal planar, C2 = tetrahedral
C) C1 = trigonal pyramidal, C2 = see-saw
D) C1 = tetrahedral, C2 = linear
E) C1 = trigonal planar, C2= bent
3) According to the following thermochemical equation, what mass of H2O (in g) must form in
order to produce 975 kJ of energy?
SiO2(s) + 4 HF(g) → SiF4(g) + 2 H2O(l)
A) 54.1 g
B) 68.0 g
C) 191 g
D) 95.5 g
ΔH°rxn = -184 kJ
E) 102 g
4) Use the standard reaction enthalpies given below to determine ΔH°rxn for the following
reaction:
4 SO3(g) → 4 S(s) + 6 O2(g) ΔH°rxn = ?
Given:
SO2(g) → S(s) + O2(g)
ΔH°rxn = +296.8 kJ
2 SO2(g) + O2(g) → 2 SO3(g) ΔH°rxn = -197.8 kJ
A) -692.4 kJ
B) -293.0 kJ
C) -494.6 kJ
D) 1583 kJ
E) -791.4 kJ
5) A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the
following reaction. If the temperature rises from 25.0 to 62.3°C, determine the heat capacity of
the calorimeter. The molar mass of ethanol is 46.07 g/mol.
C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(g) ΔH°rxn = -1235 kJ
A) 63.7 kJ/°C
B) 4.99 kJ/°C
C) 15.7 kJ/°C
D) 5.65 kJ/°C
E) 33.1 kJ/°C
6) Each of the following sets of quantum numbers is supposed to specify an orbital. Choose the
one set of quantum numbers that does not contain an error.
A) n = 3, l = 2, ml =+3
B) n = 4, l = 4, ml =0
C) n = 3, l = 1, ml = -2
D) n = 5, l = 3, ml =-3
E) n = 4, l = 0, ml =-1
7) Determine the shortest frequency of light required to remove an electron from a sample of Ti
metal, if the binding energy of titanium is 3.14 × 103 kJ/mol.
A) 6.19 x 1015 Hz
B) 2.11 x 1015 Hz
C) 7.87 x 1015 Hz
D) 1.27 x 1015 Hz
E) 4.74 x 1015 Hz
8) For hydrogen, what is the wavelength of the photon emitted when an electron drops from a
4d orbital to a 2p orbital in a hydrogen atom? The Rydberg constant is 1.097 × 10-2 nm-1.
A) 2.057 × 10-3 nm
B) 656.3 nm
C) 486.2 nm
D) 364.6 nm
9) What are the possible values of n and ml for an electron in a 4d orbital?
A) n = 4 and ml = 2
B) n = 5 and ml = -2, -1, 0, +1, +2
C) n = 1, 2, 3, or 4 and ml = 2
D) n = 1, 2, 3, or 4 and ml = -2, -1, 0, +1, or +2
10) Give the ground state electron configuration for I.
A) [Kr]5s24d105p6
B) [Kr]5s25d105p6
C) [Kr]5s24d105p5
D) [Kr]5s25p6
E) [Kr]4d105p6
11) Give the set of four quantum numbers that could represent the last electron added (using the
Aufbau principle) to the Ne atom.
A) n = 3, l = 0, ml = 1, ms = B) n = 3, l =2 , ml = 1, ms = C) n = 2, l = 1, ml = 1, ms = D) n = 3, l = 1, ml = 1, ms = +
E) n = 3, l = 2, ml =1 , ms = +
12) What is the molecular geometry of TeCl4?
A) tetrahedral
B) seesaw
C) square pyramidal
D) square planar
13) What is the molecular geometry of NCl3?
A) T-shaped
B) tetrahedral
C) trigonal pyramidal
D) trigonal planar
14) Use the molecular orbital diagram shown to determine which of the following is most
stable.
A) F2 B) F22⁺
C) F22⁻
D) O22⁺
E) Ne22⁺
15) Draw the Lewis structure for SF6. What is the hybridization on the S atom?
A) sp3
B) sp3d2
C) sp D) sp3d
E) sp2
16) How many of the following molecules contain at least one pi bond?
C2H6 Cl2CO C2Cl4 SeS3
A) 1 B) 4 C) 0 D) 3 E) 2
17) Using the VSEPR model, the molecular geometry of the central atom in XeF2 is
__________.
A) tetrahedral
B) trigonal pyramidal
C) linear
D) bent
E) trigonal planar
18) What is the O-B-O bond angle in BO33-?
A) greater than 120°
B) 109.5°
C) 120° D) less than 109.5°
19) How many lone pairs of electrons are on the S atom in SF4 ?
A) 2
B) 1
C) 0
D) 3
20) The VSEPR model predicts the HOH bond angle in H3O+ to be
A) 109.5°.
B) 60°.
C) 90°.
D) less than 109.5° but greater than 90°.
21) Using the VSEPR model, the electron-domain geometry of the central atom in SF2 is
__________.
A) trigonal planar
B) octahedral
C) linear
D) trigonal bipyramidal
E) tetrahedral
22) The osmotic pressure of a solution formed by dissolving 25.0 mg of aspirin
0.250 L of water at 25°C is __________ atm.
in
A) 1.14 ×
B) 1.38
C) 0.0136
D) 13.6
E) 2.45
23) Based on the figure above, the boiling point of diethyl ether under an external pressure of
is __________°C.
A) 40 B) 0 C) 20 D) 10 E) 30
24) Based on the figure above, the boiling point of ethyl alcohol under an external pressure of
is
A) 40 B) 80 C) 70 D) 20 E) 60
25) A solution is prepared by dissolving 7.00 g of glycerin (
) in 201 g of ethanol
The freezing point of the solution is __________°C. The freezing point of pure
ethanol is
at 1 atm. The molal-freezing-point-depression constant ( ) for ethanol is
The molar masses of glycerin and of ethanol are 92.1 g/mol and 46.1 g/mol,
respectively.
A) -107.9 B) 0.752
C) -115.4 D) -113.8 E) -121.3
26) At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2
mm Hg, respectively. Calculate the total vapor pressure over a solution of benzene and toluene
with Xbenzene = 0.580.
A) 131 mm Hg
B) 106 mm Hg
C) 121 mm Hg
D) 242 mm Hg
27) The Henry's law constant for helium gas in water at 30°C is 3.70 ×
M/atm. When the
partial pressure of helium above a sample of water is 0.650 atm, the concentration of helium in
the water is __________ M.
A) 1.76 × 103
B) 1.30
C) 5.69 × 10-4
D) 2.41 × 10-4
E) 3.70 ×
1) D
2) B
3) C
4) D
5) C
6) D
7) C
8) C
9) B
10) C
11) C
12) B
13) C
14) D
15) B
16) D
17) C
18) C
19) B
20) D
21) E
22) C
23) A
24) D
25) C
26) A
27) D