Reference no: EM131125017

1. Which of the following best describes how water molecules interact with cations and anions of ionic compound?

a. The positive end of the water dipole moment aligns toward the anion

b. The negative end of the water dipole moment aligns toward the cation

c. The positive end of the water dipole moment aligns toward the anion and the negative end of the water dipole moment aligns toward the cation

d. hydrogen bonding

2. 2.0 moles of a nonelectrolyte solute are added to 1.0 kg of an unknown solvent. The freezing point is depressed by 7.9 K. Calculate the molal freezing point constant (Kf?) for this solvent.

a. 7.9 K kg /?mol

b. 0.25 K kg /?mol

c. 3.95 K kg /?mol

d. 15.8 K kg /?mol

3. Osmotic pressure a particularly useful way to characterize solutions becuase

a. osmotic pressure is easier to measure than other properties of solutions..

b. osmotic pressure is particularly sensitive to small changes in solute concentration.

c. osmotic pressure is not a colligative property

d. osmotic pressure works for all ideal solutions.

4. Which of the following has the highest osmotic pressure?

a. pure water

b. 0.10 M solution of C₆H₁₂O₆ in water

c. 0.10 M solution of NaCl in water

d. 0.10 M solution of CaCl₂ in water

5. Consider the half-reaction below (in an acidic solution).

NO₃-?(aq) --> NO(g)

Which of the following is needed to balance this half-reaction?

a. 3e - are needed on the reactants side.

b. All of these are needed to balance the given reaction.

c. 2 H₂O are needed on the products side.

d. 4H?+ are needed on the reactants side.

6. All of the following have a dipole moment EXCEPT

a. ammonia

b. acetone

c. carbon tetrachloride

d. methylene chloride

7. Arrange the following phases of matter in decreasing degrees of freedom.

a. Gas, liquid, solid

b. Solid, liquid, gas

c. Liquid, gas, solid

d. Gas, solid, liquid

8. What term refers to the intermolecular attraction between molecules of the same compound?

a. Adhesion

b. Cohesion

c. Magnetism

d. Meniscus

9. Select the BEST definition for equilibrium vapor pressure:

a. The pressure exerted by the vapor of a substance at room temperature when one mole of vapor is present in a container whose volume is one liter.

b. The pressure exerted by the vapor on the walls of a container that contains both liquid and gas phases of the substance.

c. The pressure exerted at a given temperature by a vapor in equilibrium with the same substance in liquid form.

10. What is the critical point?

a. The combination of temperature and pressure where solid, liquid and gas are all in equilibrium.

b. Another name for the boiling point at exactly 1 atm.

c. The temperature and pressure above which the distinction between liquid and gas disappears.

d. The point at which the solid-liquid line ends.

11. Diamond is a covalent network solid, meaning that each atom in a crystal of diamond

a. contributes electrons to a non-localized electron cloud.

b. donates electrons to neighboring atoms, forming ions.

c. shares electrons with all the surrounding atoms, forming covalent bonds.

d. is held in place by dipole-dipole forces.

12. A silver crystal has a face-centered cubic unit cell. This is the closest silver atoms can be packed. What fraction of the unit cell in a silver crystal is empty space? The radius of a silver atom is 144 pm (though you don't technically need this number to answer the question).

a. 65%

b. 35%

c. 26%

d. 74%

13. When 3.00 g KNO₃ are dissolved in 50 g glycerol, the freezing point changes from 17.8°C to 13.6°C. What is the freezing point depression constant (Kf ) for glycerol?

a. 3.5 K/m

b. 3,500 K/m

c. 7.1 K/m

d. 14.2 K/m

14. A certain type of sugar dissolves in water, but the solution created does not conduct electricity. Therefore, the sugar does not form ions when dissolved in solution. When 10.0 g of this sugar are dissolved in 25.0 g of water, the freezing point of the solution is -5.0°C. If the freezing point depression constant for water (Kf) is 1.86°C/m, what is the molar mass of the sugar?

a. 55 g/mol

b. 83 g/mol

c. 130 g/mol

d. 150 g/mol

15. Suppose you add 4.25 g of naphthalene, C₁₀H₈, to 67.9 g of benzene, C6H6, and they form an ideal solution. The vapor pressure of pure benzene is 0.1252 atm at the temperature of the experiment. What is the vapor pressure of the benzene above the solution?

The molar mass of naphthalene is 128.17 g /?mole and the molar mass of benzene is 78.0 g /?mol.

a. 0.904 atm

b. 0.033 atm

c. 0.121 atm

d. 0.1252 atm

16. Potassium chloride is used in the kitchen as a salt substitute (in place of sodium chloride). Suppose you were planning to make ice cream but discovered too late that you were out of table salt for making the ice bath. If the recipe called for one pound of NaCl, how would it work to use one pound of KCl instead?

a. Using KCl would give a solution with a slightly higher freezing point.

b. Using KCl would give a solution with a slightly lower freezing point.

c. Using KCl would give a solution with exactly the same freezing point.

17. What is the boiling point of a solution that contains 5.0 g of NaCl dissolved in 25 g of water (Kb for water is 0.51)?

a. 107.3°C

b. 101.7°C

c. 103.5°C

d. 100.4°C

18. Sodium chloride has solubility in water at 100.0°C of 39.1 g sodium chloride per 100 g of water. Calculate the boiling point of a saturated solution of sodium chloride in water. At this concentration, ν is 1.85; Kb for water is 0.513°C /?m.

a. 103.4°C

b. 106.3°C

c. 6.34°C

d. 106.8°C

19. To determine the molar mass of an unknown protein, 1.00 mg was dissolved in 1.00 mL of water. At 25.0°C the osmotic pressure of this solution was found to be 1.47 × 10-3 atm. What is the molar mass of this protein?

a. 1.66 × 104 g /?mole.

b. 1.40 × 103 g /?mole.

c. 1.66 × 10-9 g /?mole

d. 6.01 × 10-5 g /?mole

20. What is the osmotic pressure of human blood at 37°C if human blood is isotonic to 0.16 M NaCl solution? Remember that NaCl almost completely ionizes in water, so each formula unit of NaCl contributes two particles to the solution.

a. 4.1 atm

b. 0.5 atm

c. 8.1 atm

d. 0.097 atm

21. Correct the following incorrectly balanced reaction?

2HNO₂(aq) + 2HI(aq) → 2NO(g) + 2I₂(aq) + 2H₂O(l)

a. The coefficient on HNO₂ should be 3.

b. The coefficient on HI should be 4.

c. The coefficient on H₂O should be 3.

d. The coefficient on I 2 should be 1.

22. What are the oxidation numbers of potassium, sulfur, and oxygen, respectively, in K₂SO₄?

a. +1, +6, -2

b. 0, 4, -4

c. +2, +6, -8

d. +1, +2, -1

23. Consider the combustion of methane to form carbon dioxide and water. What is the oxidation state change for carbon in this reaction?

a. from +4 to -2

b. from -2 to +4

c. from -4 to +4

d. from 0 to +4

24. Permanganate can be used to oxidize oxalic acid all the way to carbon dioxide. If you balance this redox reaction in acidic solution, which of the following statements about the balanced reaction is not true?

MnO₄^- (aq) + H₂C₂O₄(aq) → Mn₂+?(aq) + CO₂(aq)

a. The oxidation state of Mn changes from +7 to +2.

b. 10 equivalents of CO₂ are produced.

c. 16 equivalents of H?⁺ are required.

d. Each equivalent of MnO₄- will react with 5 equivalents of oxalic acid.

25. Balance the following redox reaction in acid. What is the coefficient on H ⁺?

CuS(s) + NO₃^- (aq) → Cu₂+?(aq) + SO₄^2- (aq) + NO(g)

a. 3

b. 5

c. 8

d. 10

26. Suppose that you have to balance the following half-reaction in basic solution.

Cr₂O₇^2- (aq) → Cr³⁺ (aq)

What is the coefficient on water of the final balanced half-cell reaction?

a. 5

b. 6

c. 7

d. 8

27. The redox activity series lists reactions as

M?n⁺ + n e ^- → M

with lithium at the top and gold at the bottom. Which statement best describes the redox activity series?

a. The list is in order of molar mass with lithium at the top. Gold is the heaviest metal in the table.

b. The list is in order of number of electrons removed from the metal, so n = 1 at the top and n = 3 at the bottom.

c. The list is alphabetical.

d. It is easiest to oxidize elements at the top of the list and it gets harder as you go down the series.

28. Zinc can displace lead ions from solution in the following manner:

Zn(s) + Pb²⁺ (aq) → Zn²⁺ (aq) + Pb(s)

In an expanded redox activity series, the reaction of Pb²⁺ (aq) + 2e^- → Pb(s) is located below the reaction of Zn²⁺ (aq) + 2e^- → Zn(s).

Which of the following best explains why this reaction is spontaneous or nonspontaneous?

a. The reaction is spontaneous because zinc is a better reducing agent than lead.

b. The reaction is spontaneous because zinc is a better oxidizing agent than lead.

c. The reaction is nonspontaneous because lead is a better reducing agent than zinc.

d. The reaction is nonspontaneous because lead is a better oxidizing agent than zinc.

29. What other information, in addition to the spacing between planes of particles, can be obtained from the X-ray diffraction pattern of a crystal?

a. From the positions of the spots, we can determine the actual positions of atoms in the crystal.

b. From the intensities of the spots, we can determine the actual positions of atoms in the crystal.

c. From the shape of the dots, we can determine the shape of the orbitals in the atoms.

d. From the wavelength of the diffracted waves, we can determine the type of intermolecular bonds in the crystal.

30. The radius of a silver atom is 144 pm. Silver forms a face-centered cubic crystal. What is the length of the unit cell in a silver atom?

a. 407 pm

b. 203 pm

c. 288 pm

d. 408.6 pm

31. Titanium crystallizes on a body-centered cubic lattice with a unit cell edge length of 3.28 Å. The density of titanium is 4.54 g /?cm³. The atomic mass of titanium is 47.88. Using this information, calculate Avogadro's number.

a. 5.98 × 10²³

b. 6.02 × 10²³

c. 1.20 × 10²⁴

d. 5.98 × 10²⁸