CHM2045 S13 Final.tst

CHM2045 S13 Final Exam
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) How will the osmotic pressure of an aqueous solution change as evaporation occurs?
A) The osmotic pressure will increase.
B) The osmotic pressure will decrease.
C) The osmotic pressure will not change.
D) The osmotic pressure will increase or decrease until it equals the vapor pressure of water.
2) In most liquid solutions, the component present in the larger amount is called the
A) dispersed medium.
B) solute.
C) solvent.
D) emulsifying agent.
3) Indicate which is larger in each of the following two sets.
(I) Cr 3+ or Cr
(II) Se2- or Se
A) Cr3+ is larger than Cr and Se is larger than Se 2-.
B) Cr is larger than Cr3+ and Se2- is larger than Se.
C) Cr3+ is larger than Cr and Se2- is larger than Se.
D) Cr is larger than Cr3+ and Se is larger than Se2-.
4) Which is the longest bond?
A) NN
B) NN
C) N=N
D) All three bond lengths should be about the same.
5) The absorption of radiation of frequency 1.16 × 10 11 Hz is required for CO molecules to go from the lowest
rotational energy level to the next highest rotational energy level. Determine the energy for this transition in
kJ/mol. h = 6.626 × 10 -34 J ∙ s. NA = 6.022 × 10 23 mol-1.
A) 7.69 × 10 -23 kJ/mol
B) 46.3 kJ/mol
C) 0.0463 kJ/mol
D) 949 kJ/mol
6) A 0.50 m solution of which solute has the largest van't Hoff factor?
A) K3PO4
B) NaNO 3
C) CaCl2
D) LiCO3
7) Which is the best description of the bonding in NO3-?
A) 3 N-O ! bonds and 3 N-O " bonds
B) no N-O ! bonds and delocalized N-O " molecular orbitals extending over all four atoms
C) 3 N-O ! bonds and delocalized N-O " molecular orbitals extending over all four atoms
D) 3 N-O ! bonds and no N-O " bonds
8) Identify the set of hybrid orbitals shown below.
B) sp2
D) none of the above
A) sp
C) sp3
9) Which of the following would be expected to exhibit the Tyndall effect?
A) Pure water
B) Soap in water
C) NaCl in water
D) Pure ethanol
10) You are given two flasks of equal volume. One contains H2 at 0°C and 1 atm while the other contains CO2 at
0°C and 2 atm. Which of the following quantities will be the same for both flasks?
A) density
B) number of molecules present
C) average molecular kinetic energy
D) average molecular speed
11) Identify the packing in the figure shown below.
A) body-centered cubic
C) hexagonal closest packed
B) cubic closest packed (face-centered cubic)
D) simple cubic
12) In the emission spectrum of the H-atom, which transition would have the longest wavelength for its
emitted photon?
A) n = 6 → n = 5
B) n = 7 → n = 3
C) n = 5 → n = 1
D) n = 3 → n = 2
13) Which group of elements are found as diatomic molecules?
A) alkali metals
B) alkaline earth metals
C) halogens
D) noble gases
14) Which two ions have the same electron configuration in the ground state?
A) Fe 2+ and Fe 3+
B) Se2+ and IC) Ba2+ and I-
D) Rb + and Cs+
15) The phase diagram of a substance is shown above. The area labeled __________ indicates the gas phase for
the substance.
A) w
B) x
C) y
D) z
16) How many liters of oxygen are needed to exactly react with 27.8 g of methane at STP?
CH4(g) + 2 O2(g) → CO 2(g) + 2 H2O(l)
A) 19.5 L
B) 85.0 L
C) 77.6 L
D) 39.0 L
17) Which of the following is true? The probability density
A) for all s orbitals is independent of distance from the nucleus.
B) is independent of distance from the nucleus for 1s orbitals only.
C) is independent of direction from the nucleus for 1s orbitals only.
D) for all s orbitals is independent of direction from the nucleus.
18) Arrange the following spectral regions in order of increasing wavelength:
infrared, microwave, ultraviolet, visible.
A) ultraviolet < visible < infrared < microwave
B) microwave < visible < infrared < ultraviolet
C) ultraviolet < infrared < visible < microwave
D) microwave < infrared < visible < ultraviolet
The following four spheres represent a metal atom, a nonmetal atom, a monatomic anion and a monatomic cation, not
necessarily in that order. The illustration depicts the reaction A + B → C + D.
19) Which sphere represents the nonmetal atom?
A) A
B) B
C) C
D) D
Use the diagram below to answer the following questions.
20) The temperature and pressure at which all three phases can coexist in equilibrium is
A) 0.25 atm and 110°C.
B) 1.25 atm and 300°C.
C) 0.45 atm and 130°C.
D) 1.0 atm and 140°C.
The following ball-and-stick molecular model is a representation of the amino acid alanine (unshaded spheres = H). Only
the connections between atoms are shown; multiple bonds and nonbonded electrons are not indicated.
21) In order to complete an electron-dot structure of alanine, the nitrogen atom needs
A) 1 nonbonded pair of electrons.
B) 2 nonbonded pairs of electrons.
C) 1 additional bond and 1 nonbonded pair of electrons.
D) 1 additional bond and 2 nonbonded pairs of electrons.
22) Which covalent bond is the most polar?
A) C-F
B) N-F
C) F-F
D) Cl-F
23) Atoms of which element, indicated by letter on the periodic table, have the orbital-filling diagram shown
A) A
B) B
C) C
D) D
24) Which orbital-filling diagram violates the Pauli exclusion principle?
25) A saturated solution is defined as
A) a solution that is in equilibrium with both pure solvent and undissolved solute.
B) a solution that is in equilibrium with pure solvent.
C) a solution that is in equilibrium with undissolved solute.
D) a concentrated solution.
26) An aqueous solution has a normal boiling point of 102.0°C. What is the freezing point of this solution? For
water K b is 0.51°C/ and K f = 1.86°C/m.
A) -0.55°C
B) -7.3°C
C) -2.0°C
D) -3.6°C
27) What is the bond angle in the following molecular model of H2S?
A) less than 109.5°
C) less than 120° but greater than 109.5°
B) 109.5°
D) 120°
28) Which of the following would have a density of 1.21 g/L at 7.0°C and 0.987 atm?
A) Ne
B) Ar
C) O2
D) N2
29) Which concentration becomes smaller as the temperature is increased from 20°C to 80°C?
A) molality
B) molarity
C) mole fraction
D) mass %
30) How many lone pairs of electrons are on the Xe atom in XeF 6?
A) 0
B) 1
C) 2
D) 3
The spheres below represent atoms of Sb, As, P, and N (not necessarily in that order).
31) Which one of these spheres represents an atom of Sb?
A) sphere (a)
B) sphere (b)
C) sphere (c)
D) sphere (d)
32) Molecules of a liquid can pass into the vapor phase only if the
A) molecules have sufficient kinetic energy to overcome the intermolecular forces in the liquid.
B) temperature of the liquid is near its boiling point.
C) vapor pressure of the liquid is high.
D) liquid has little surface tension.
33) How many atoms are in one body-centered cubic unit cell of a metal?
A) 1
B) 2
C) 3
D) 4
34) List the elements Na, Ca, Rb, Cl, He in order of decreasing first ionization energy.
A) Rb > Ca > Cl > Na > He
B) He > Cl > Ca > Na > Rb
C) He > Na > Ca > Cl > Rb
D) He > Na > Cl > Ca > Rb
35) Which cation in each set is expected to have the larger ion-dipole intermolecular forces in water?
I Mg 2+ or Ba 2+
II K+ or Al3+
A) Ba2+ in set I and Al 3+ in set II
B) Mg2+ in set I and K+ in set II
C) Mg2+ in set I and Al 3+ in set II
D) Ba2+ in set I and K+ in set II
36) Which of the following statements is not consistent with the properties of a molecular solid?
A) a solid formed by the combination of two nonmetallic elements
B) a compound that conducts electricity when molten
C) a low melting solid
D) a solid that is a nonconductor of electricity
37) Arrange the following compounds in order of their expected increasing solubility in water:
38) Which of the following instruments directly measures the pressure of a gas?
A) spectrometer
B) gas chromatograph
C) manometer
D) polarimeter
39) What is the ground-state electron configuration of Co?
A) [Ar]4s13d8
B) [Ar]3d9
C) [Ar]4s24p64d1
D) [Ar]4s23d7
40) Aqueous solutions of 30% (by weight) hydrogen peroxide, H2O2, are used to oxidize metals or organic
molecules in chemical reactions. Given that the density of the solution is 1.11 g/mL, calculate the molarity.
A) 6.78 M
B) 9.79 M
C) 12.6 M
D) 0.794 M
41) Which of the following molecules would be expected to have a non-zero (# > 0) permanent dipole moment?
A) SF4
B) O=C=C=C=O
C) CO2
D) SF6
42) An "empty" aerosol can at 25°C still contains gas at 1.00 atmosphere pressure. If an "empty" can is thrown
into a 475°C fire, what is the final pressure in the heated can?
A) 19.0 atm
B) 5.26 × 10 -2 atm
C) 2.51 atm
D) 0.398 atm
43) What is a quantum of light called?
A) the wavelength
B) the frequency
C) the amplitude
D) a photon
44) In which case should CO 2(g) be more soluble in water?
A) The total pressure is 3 atm and the partial pressure of CO 2 is 2 atm.
B) The total pressure is 1 atm and the partial pressure of CO 2 is 0.03 atm.
C) The total pressure is 1 atm and the partial pressure of CO 2 is 0.5 atm.
D) The total pressure is 5 atm and the partial pressure of CO 2 is 1 atm.
45) Naproxen is a commercially important anti-inflammatory agent. A solution of 1.138 g of naproxen in 25.00 g
benzene has an osmotic pressure of 4.00 atm at 20°C. The solution volume is 29.75 mL. Calculate the molar
mass of naproxen, assuming it remains intact upon dissolution and the density of the solution equals the
density of pure benzene.
A) 3.80 × 10 5 g/mol
B) 176 g/mol
C) 307 g/mol
D) 230 g/mol
Answer Key
Testname: CHM2045 S13 FINAL
1) A
2) C
3) B
4) A
5) C
6) A
7) C
8) B
9) B
10) C
11) D
12) A
13) C
14) C
15) C
16) C
17) D
18) A
19) B
20) C
21) A
22) A
23) B
24) D
25) C
26) B
27) A
28) D
29) B
30) B
31) D
32) A
33) B
34) B
35) C
36) B
37) A
38) C
39) D
40) B
41) A
42) C
43) D
44) A
45) D