ACHM 121 Exam 1 with all correct detailed
questions and answers already graded A+
1. Determine the boiling point elevation of a solution that contains 22.5 g of glucose in 500.0 g ethanol
(glucose C6H12O6 molar mass = 180.156 g/mol, ethanol Kb = 1.22°C/m.)
0.305°C
27.32°C
3.05°C
22.2°C
0.610°C
2. How much energy is required to heat 81.0 g H2O from a liquid at 65°C to a gas at 115°C?
The following physcial data may be helpful.
63.5 kJ
52.7 kJ
10.9 kJ
197 kJ
190 kJ
3. In the phrase "like disolves like" what is alike between soluble solutes and solvents?
intermolecular forces
melting point
molar mass
density
4. Of the following substances, only __________ has London dispersion forces as
its only intermolecular force.
HCl
CH4
NH3
CH3OH
None of the above
5. Pairs of liquids that will mix in all proportions are called __________ liquids.
miscible
saturated
supersaturated
unsaturated
, polar liquids
6. Place the following compounds in order of decreasing boiling point.
I. CH3CH2CH3 II. CH3CH2OH III. (CH3)2C=O
I > III > II
I > II > III
III > II > I
III > I > II
II > III > I
7. Predict which of the following substances would have the highest ΔHvap.
C8H18
H2
F2
Ar
CCl4
8. What is the ideal value of i (van't Hoff factor) for (NH4)3PO4?
1
2
3
4
5
9. What is the osmotic pressure (in atm) of a solution formed by dissolving 2.5 g of aspirin (C9H8O4) in
0.250L of water at 25°C ?
13.6
0.0136
1.36
2.45
0.245
10. What is the strongest type of intermolecular force present in SO2 ?
, hydrogen bonding
ion-dipole
dipole-dipole
dispersion
None of the above
11. Which of the following aqueous solutions will have the highest boiling point?
0.20 m glucose
0.10 m Na2SO4
0.10 m SrSO4
0.25 m sucrose
0.10 m NaCl
12. Which of the following choices has the compounds correctly arranged in order of increasing solubility
in water? (least soluble to most soluble)
CH4 < NaNO3 < CHCl3
CCl4 < CHCl3 < NaNO3
CH3OH < CH4 < LiF
CH3OH < CCl4 < CHCl3
LiF < NaNO3 < CHCl3
13. Which of the following should have the largest Henry's law constant (kH) in water?
CH4
HCl
CO2
Xe
Ar
14. Which of the following statements is TRUE? Please read carefully.
For molecules with similar molar masses, dispersion forces are generally stronger than
hydrogen bonding forces.
Intermolecular forces hold the atoms in covalent molecules together.
Molecules with weak intermolecular forces generally have a high vapor pressure.
Vapor pressure decreases when temperature increases.
None of the above is true.
15. A sample of butane (C4H10) is vaporized at its boiling point. How much energy is required to vaporize
a 142 g sample of butane if its DHvap is 24.3 kJ/mol? The molar mass of butane is 58.12 g/mol.
, 244 kJ
166 kJ
16.2 kJ
59.4 kJ
200 kJ
16. A solution contains 11% by mass of sodium chloride. This means that __________.
100 g of the solution contains 11 g of sodium chloride
the density of the solution is 11 g/mL
there are 11 g of sodium chloride in in 1.0 mL of this solution
the molality of the solution is 11
100 mL of the solution contains 11 g of sodium chloride
17. As a solid element melts, the atoms become __________ and they have __________ attraction for
one another.
larger, greater
more separated, less
more separated, more
closer together, more
closer together, less
18. Calculate the freezing point of a 0.04250 m aqueous solution of NaNO3. The molal freezing-point-
depression constant of water is
-0.158
0.0425
-0.0790
-0.316
0.0790
19. Colligative properties depend on
The number of particles dissolved
The molar mass of the solute
The chemical properties of the solvent
The Tyndall effect
The chemical properties of the solute
20. Colligative properties of solutions include all of the following except __________.
elevation of the boiling point of a solution upon addition of a solute to a solvent
depression of the freezing point of a solution upon addition of a solute to a solvent
an increase in the osmotic pressure of a solution upon the addition of more solute
questions and answers already graded A+
1. Determine the boiling point elevation of a solution that contains 22.5 g of glucose in 500.0 g ethanol
(glucose C6H12O6 molar mass = 180.156 g/mol, ethanol Kb = 1.22°C/m.)
0.305°C
27.32°C
3.05°C
22.2°C
0.610°C
2. How much energy is required to heat 81.0 g H2O from a liquid at 65°C to a gas at 115°C?
The following physcial data may be helpful.
63.5 kJ
52.7 kJ
10.9 kJ
197 kJ
190 kJ
3. In the phrase "like disolves like" what is alike between soluble solutes and solvents?
intermolecular forces
melting point
molar mass
density
4. Of the following substances, only __________ has London dispersion forces as
its only intermolecular force.
HCl
CH4
NH3
CH3OH
None of the above
5. Pairs of liquids that will mix in all proportions are called __________ liquids.
miscible
saturated
supersaturated
unsaturated
, polar liquids
6. Place the following compounds in order of decreasing boiling point.
I. CH3CH2CH3 II. CH3CH2OH III. (CH3)2C=O
I > III > II
I > II > III
III > II > I
III > I > II
II > III > I
7. Predict which of the following substances would have the highest ΔHvap.
C8H18
H2
F2
Ar
CCl4
8. What is the ideal value of i (van't Hoff factor) for (NH4)3PO4?
1
2
3
4
5
9. What is the osmotic pressure (in atm) of a solution formed by dissolving 2.5 g of aspirin (C9H8O4) in
0.250L of water at 25°C ?
13.6
0.0136
1.36
2.45
0.245
10. What is the strongest type of intermolecular force present in SO2 ?
, hydrogen bonding
ion-dipole
dipole-dipole
dispersion
None of the above
11. Which of the following aqueous solutions will have the highest boiling point?
0.20 m glucose
0.10 m Na2SO4
0.10 m SrSO4
0.25 m sucrose
0.10 m NaCl
12. Which of the following choices has the compounds correctly arranged in order of increasing solubility
in water? (least soluble to most soluble)
CH4 < NaNO3 < CHCl3
CCl4 < CHCl3 < NaNO3
CH3OH < CH4 < LiF
CH3OH < CCl4 < CHCl3
LiF < NaNO3 < CHCl3
13. Which of the following should have the largest Henry's law constant (kH) in water?
CH4
HCl
CO2
Xe
Ar
14. Which of the following statements is TRUE? Please read carefully.
For molecules with similar molar masses, dispersion forces are generally stronger than
hydrogen bonding forces.
Intermolecular forces hold the atoms in covalent molecules together.
Molecules with weak intermolecular forces generally have a high vapor pressure.
Vapor pressure decreases when temperature increases.
None of the above is true.
15. A sample of butane (C4H10) is vaporized at its boiling point. How much energy is required to vaporize
a 142 g sample of butane if its DHvap is 24.3 kJ/mol? The molar mass of butane is 58.12 g/mol.
, 244 kJ
166 kJ
16.2 kJ
59.4 kJ
200 kJ
16. A solution contains 11% by mass of sodium chloride. This means that __________.
100 g of the solution contains 11 g of sodium chloride
the density of the solution is 11 g/mL
there are 11 g of sodium chloride in in 1.0 mL of this solution
the molality of the solution is 11
100 mL of the solution contains 11 g of sodium chloride
17. As a solid element melts, the atoms become __________ and they have __________ attraction for
one another.
larger, greater
more separated, less
more separated, more
closer together, more
closer together, less
18. Calculate the freezing point of a 0.04250 m aqueous solution of NaNO3. The molal freezing-point-
depression constant of water is
-0.158
0.0425
-0.0790
-0.316
0.0790
19. Colligative properties depend on
The number of particles dissolved
The molar mass of the solute
The chemical properties of the solvent
The Tyndall effect
The chemical properties of the solute
20. Colligative properties of solutions include all of the following except __________.
elevation of the boiling point of a solution upon addition of a solute to a solvent
depression of the freezing point of a solution upon addition of a solute to a solvent
an increase in the osmotic pressure of a solution upon the addition of more solute
