This document appears to be an exam for a chemistry course. It contains 27 multiple choice questions testing concepts related to intermolecular forces, phase diagrams, solutions, and chemical kinetics. The key at the bottom provides the correct answer for each question.

1. October 06 Chem 1412_____________________ _____________________
Exam 2 1.LAST Name 1st on Scantron
2. Turn in Scantron Only
READ DIRECTIONS ---------> 3. Do Not Erase Scantron
4. Bonus on Back of ScantronAS SHOWN
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Of the following substances, only __________ has London dispersion forces as its only 1)
intermolecular force.
A) CH3 OH B) CH4 C) H2 S D) NH3 E) HCl
2) Which one of the following exhibits dipole-dipole attraction between molecules? 2)
A) AsH3 B) Cl2 C) BCl3 D) CO2 E) XeF4
3) The predominant intermolecular force in (CH3 )2 NH is __________. 3)
A) London dispersion forces
B) ionic bonding
C) hydrogen bonding
D) ion-dipole forces
E) dipole-dipole forces
4) Which statements about viscosity are true? 4)
(i) Viscosity increases as temperature decreases.
(ii) Viscosity increases as molecular weight increases.
(iii) Viscosity increases as intermolecular forces increase.
A) (i) only
B) (i) and (iii)
C) (ii) and (iii)
D) none
E) all
5) The shape of a liquid's meniscus is determined by __________. 5)
A) the type of material the container is made of
B) the relative magnitudes of cohesive forces in the liquid and adhesive forces between the
liquid and its container
C) the amount of hydrogen bonding in the liquid
D) the viscosity of the liquid
E) the volume of the liquid
1

2. 6) The vapor pressure of a liquid __________. 6)
A) decreases linearly with increasing temperature
B) is totally unrelated to its molecular structure
C) increases nonlinearly with increasing temperature
D) increases linearly with increasing temperature
E) decreases nonlinearly with increasing temperature
7) The critical temperature and pressure of CS2 are 279°C and 78 atm, respectively. At temperatures 7)
above 279°C, CS2 can only occur as a __________.
A) liquid
B) solid
C) liquid and gas
D) supercritical fluid
E) gas
8) Heat of sublimation can be approximated by adding together __________ and __________. 8)
A) heat of deposition, heat of vaporization
B) heat of freezing (solidification), heat of condensation
C) heat of fusion, heat of vaporization
D) heat of freezing (solidification), heat of vaporization
E) heat of fusion, heat of condensation
9) The phase diagram of a substance is given above. The region that corresponds to the solid phase is 9)
__________.
A) w B) x C) y D) z E) x and y

3. 10) The normal boiling point of the substance with the phase diagram shown above is __________ °C. 10)
A) 10 B) 20 C) 30 D) 40 E) 50
11) The phase diagram of a substance is given above. This substance is a __________ at 25°C and 1.0 11)
atm.
A) supercritical fluid
B) crystal
C) solid
D) gas
E) liquid
12) On a phase diagram, the critical pressure is __________. 12)
A) the pressure above which a substance is a liquid at all temperatures
B) the pressure at which a liquid changes to a gas
C) the pressure required to liquefy a gas at its critical temperature
D) the pressure below which a substance is a solid at all temperatures
E) the pressure required to melt a solid
13) On a phase diagram, the critical temperature is __________. 13)
A) the temperature below which a gas cannot be liquefied
B) the temperature required to cause sublimation of a solid
C) the temperature required to melt a solid
D) the temperature above which a gas cannot be liquefied
E) the temperature at which all three states are in equilibrium
14) A 0.100 m solution of which one of the following solutes will have the lowest vapor pressure? 14)
A) Al(ClO4 )3 B) NaCl C) Ca(ClO4 )2 D) KClO4 E) sucrose

4. 15) When aqueous solutions of __________ are mixed, a precipitate forms. 15)
A) K2 SO4 and CrCl3
B) NiBr2 and AgNO3
C) Li2 CO3 and CsI
D) NaI and KBr
E) KOH and Ba(NO3 )2
16) The principal reason for the extremely low solubility of NaCl in benzene (C6 H6 ) is the __________. 16)
A) weak solvation of Na+ and Cl- by C6H6
B) strong solvent-solvent interactions
C) increased disorder due to mixing of solute and solvent
D) hydrogen bonding in C6 H6
E) strength of the covalent bond in NaCl
17) A solution contains 15 ppm of benzene. The density of the solution is 1.00 g/mL. This means that 17)
__________.
A) 1.0 L of the solution contains 15 g of benzene
B) 100 g of the solution contains 15 g of benzene
C) the solution is 15% by mass of benzene
D) there are 15 mg of benzene in 1.0 g of this solution
E) 1.0 g of the solution contains 15 × 10-6 g of benzene
18) The vapor pressure of pure ethanol at 60 °C is 0.459 atm. Raoult's Law predicts that a solution 18)
prepared by dissolving 10.0 mmol naphthalene (nonvolatile) in 90.0 mmol ethanol will have a
vapor pressure of __________ atm.
A) 0.413 B) 0.790 C) 0.367 D) 0.0918 E) 0.498
19) The solubility of oxygen gas in water at 25 °C and 1.0 atm pressure of oxygen is 0.041 g/L. The 19)
solubility of oxygen in water at 3.0 atm and 25 °C is __________ g/L.
A) 0.041 B) 0.014 C) 0.12 D) 3.0 E) 0.31
20) A solution containing 10.0 g of an unknown liquid and 90.0 g water has a freezing point of -3.33 °C. 20)
Given Kf = 1.86 °C/m for water, the molar mass of the unknown liquid is __________ g/mol.
A) 69.0 B) 62.1 C) 161 D) 333 E) 619

5. 21) A 1.35 m aqueous solution of compound X had a boiling point of 101.4°C. Which one of the 21)
following could be compound X? The boiling point elevation constant for water is 0.52°C/m.
A) C6 H12O6
B) KCl
C) CaCl2
D) CH3 CH2OH
E) Na3 PO4
22) Which of the following is not a colloid? 22)
A) smoke
B) homogenized milk
C) fog
D) whipped cream
E) All are colloids
23) Which substance in the reaction below either appears or disappears the fastest? 23)
4NH3 + 7O2 → 4NO2 + 6H2 O
A) H2O
B) NH3
C) O2
D) NO2
E) The rates of appearance/disappearance are the same for all of these.
TRUE/FALSE.
24) The boiling points of normal hydrocarbons are higher than those of branched hydrocarbons of 24)
similar molecular weight because the London-dispersion forces between normal hydrocarbons are
greater than those between branched hydrocarbons.
25) Heats of vaporization are greater than heats of fusion. 25)
26) The value of the boiling-point-elevation constant (Kb) depends on the identity of the solvent. 26)
27) The overall reaction order is the sum of the orders of each reactant in the rate law. 27)

6. Answer Key
Testname: 1412E2F06
1) B
2) A
3) C
4) E
5) B
6) C
7) D
8) C
9) A
10) D
11) E
12) C
13) D
14) A
15) B
16) A
17) E
18) A
19) C
20) B
21) B
22) E
23) C
24) TRUE
25) TRUE
26) TRUE
27) TRUE
6