Unit 4 Review

The only intermolecular forces existing between oxygen molecules are:
1. permanent dipole forces
2. hydrogen bonding forces
3. London dispersion forces
4. ion-ion attractive forces
5. nuclear forces
Which of the following substances will have the greatest vapor pressure at 0°C?
1. NaCl
2. H₂O
3. NH₃
4. CH₄
5. H₂O and NH₃
Place the following in order of increasing strength:

1. hydrogen bonding
2. covalent bonding
3. London dispersion forces
1. 1, 2, 3
2. 3, 2, 1
3. 1, 3, 2
4. 2, 1, 3
5. 3, 1, 2
Which of the following hydrocarbons has the highest boiling point?
1. CH₄
2. C₂H₆
3. C₃H₈
4. C₄H₁₀
5. These are all gases and do not boil
A metal has crystallized with a face-centered cubic lattice. The edge of the unit cell is 366 pm. What is the diameter of the metal atom?
1. 518 pm
2. 259 pm
3. 267912 pm
4. 0.0296 pm
5. 3.98 x 10^-5 pm
For a solution in a closed container at equilibrium, which of the following pairs represent processes that must be occuring at equal rates?
1. evaporation and crystallization
2. fusion and boiling
3. evaporation and sublimation
4. crystallization and sublimation
5. evaporation and condensation
The normal boiling point of X is most likely:
1. 22°C
2. 28°C
3. 50°C
4. 80°C
5. 90°C
At a pressure of 1.3 atm and 20°C, compound X exists as:
1. a solid only
2. a solid and a liquid
3. a liquid and a gas
4. a solid and a gas
5. a liquid only
The triple point of compound X occurs at a temperature of:
1. -10°C
2. 23°C
3. 50°C
4. 80°C
5. 29°C
As the pressure increases, the melting point of compound X will:
1. increase
2. decrease
3. stay the same
4. increase and then decrease
5. decrease and then increase
An example of an amorphous solid is:
1. ice
2. quartz
3. plastic
4. diamond
5. gold
Buckminsterfullerene is one of the allotropic forms of:
1. silicon
2. semimetals
3. oxygen
4. carbon
5. steel
Which of the following statements is false?

1. Liquids with large intermolecular forces tend to have very low boiling points
2. Liquids with large intermolecular forces tend to have considerable surface tension
3. When a substance changes from a solid to a liquid, the molecules remain intact
4. The hardness of diamond is due to strong dipole-dipole attraction
1. 1 and 3
2. 2 and 4
3. 3 and 4
4. 1 and 4
5. 2 and 3
Which of the following is not an endothermic process?
1. crystallization
2. vaporization
3. melting
4. sublimation
5. combustion
How much energy is needed to convert 50.0 g of ice at -5.00°C to water at 25°C?
- Specific heat(ice) = 2.10 J/(g°C)
- Specific heat(water) = 4.18 J/(g°C)
- Heat of fusion = 333 J/g
- Heat of vaporization = 2258 J/g
1. 22.4 kJ
2. 21.9 kJ
3. 37.3 kJ
4. 175 J
5. 18.0 J
The correct order for increasing boiling point among the noble gases is:

1. He
2. Ne
3. Ar
4. Kr
5. Xe

This phenomenon is best explained in terms of:
1. hydrogen bonding
2. dipole-dipole interaction
3. covalent bonding
4. Hund's rule
5. London dispersion forces
Chromium metal crystallizes as a body-centered cubic lattice. If the atomic radius of chromium is 125 pm, what is the volume of the unit cell?
1. 289 cm³
2. 2.41 x 10⁷ cm³
3. 2.41 x 10^-23 cm³
4. 4.41 x 10⁷ cm³
5. 4.41 x 10^-23 cm³
Chromium metal crystallizes as a body-centered cubic lattice. If the atomic radius of chromium is 125 pm what is the density of chromium metal?
1. 2.09 g/cm³
2. 7.18 g/cm³
3. 7.81 g/cm³
4. 2.76 g/cm³
5. 18.90 g/cm³
Aluminum crystallized in a face-centered cubic lattice. How many aluminum atoms can be found per unit cell in this structure?
1. 1
2. 2
3. 3
4. 4
5. 8
The triple point of CO₂ is 5.2 atm and -57°C. In a laboratory at EDHS, on a day when the pressure is 758 torr and the temperature in the room is 20°C, a solid sample of carbon dioxide will:
1. freeze
2. boil
3. melt
4. remain solid
5. sublime
How many milliliters of 6.0 M HNO₃ are needed to prepare 500 mL of 0.50 M HNO₃?
1. 0.25 mL
2. 40 mL
3. 15.76 mL
4. 300 mL
5. None of these are correct
Which of the following compounds is expected to be the most soluble in water?
1. CH₃-CH₂-CH₂-CH₃
2. CH₄
3. CH₃-OH
4. CH₃-CH₂-O-CH₂-CH₃
5. CH₃-CH₂-CH₂-CH₂-OH
Find the mass percent of ZnSO₄ in a solution whose density is 1.25 g/mL and whose molarity is 1.19 M.
1. 15.4 %
2. 0.2 %
3. 23.0 %
4. 78%
5. 31.1%
Find the mole fraction of the ZnSO₄ in a solution whose density is 1.25 g/mL and whose molarity is 1.19 M ZnSO₄.
1. 1.02
2. 0.575
3. 0.0199
4. 4.09
5. 0.174
Find the molality of a solution of ZnSO₄ whose density is 1.25 g/mL and whose molarity is 1.19 M.
1. 1.12 m
2. 5.31 m
3. 0.970 m
4. 0.0571 m
5. None of these
Which of the following solute/solvent pairs best represents the principle of "like dissolves like"?
1. carbon dioxide in water
2. lipids (fats) in water
3. salt in hexane
4. hydrogen chloride in water
5. potassium iodide in benzene
The vapor pressure of water at 25.0°C is 23.8 torr. Determine the mass of sodium chloride needed to add to 400 mL of water to change the vapor pressure to 22.8 torr. Assume the density of water to be 1.0 g/mL.
1. 0.12 g
2. 54 g
3. 117 g
4. 8.15 g
5. None of these
Of the following compounds, which are not likely to increase in solubility as the temperature of the solution increases?

1. CH₄

2. NaBr

3. CO₂

4. Glucose, C₆H₁₂O₆

5. CuSO₄
1. 1 and 4
2. 2 and 3
3. 1 and 3
4. 4 only
5. 5 only
At a given temperature the vapor pressure of pure liquid diethyl ether and isopropyl alcohol are 730 torr and 310 torr, respectively. A solution prepared by mixing isopropyl alcohol and diethyl ether obeys Raoult's law. At this temperature, what is the vapor pressure of diethyl ether over a solution in which its mole fraction is 0.270?
1. 197 torr
2. 281 torr
3. 1040 torr
4. 15.7 torr
5. 0.912 torr
Which of the following properties is dependent on the amount and identity of the solute particles?
1. Freezing point of the solution
2. Boiling point of the solution
3. Osmotic pressure
4. Solution density
5. None of these
How many grams of Al₂(SO₄)₃ do you need to make 87.62 g of 0.0162 m Al₂(SO₄)₃ solution?
1. 5.54 g
2. 0.483 g
3. 0.0751 g
4. 194 g
5. 1005 g
When 18.0 grams of a substance is dissolved in 500 grams of water, the freezing point is depressed by 0.31°. What is the molar mass of the solute?
1. 3.0 g
2. 108 g
3. 216 g
4. 54 g
5. 1018 g
You are given the problem of lowering the freezing point of H₂O from 0°C to 0°F (-17.8°C), what volume of methyl alcohol (CH₃OH) should you add to 10.0 liters of H₂O? The density of CH₃OH is 0.787 g/mL. Assume the density of the water to be exactly 1.00 g/mL.
1. 32.05 mL
2. 316 mL
3. 402 mL
4. 4.02 L
5. None of these
Two sodium chloride solutions are separated by a semipermeable membrane. The concentration of solution "A" is 0.50 M and the concentration of solution "B" is 0.250 M. Over time, there will be a measurable movement of:
1. water from solution A to B
2. water from solution B to A
3. sodium chloride from solution A to B
4. sodium chloride from solution B to A
5. Two of these are correct
The expected (ideal) van't Hoff factor for a dilute solution of sodium sulfate is:
1. 1
2. 2
3. 3
4. 4
5. 5
A 0.250 M solution of CaCl₂ has an observed osmotic pressure of 10.1 atm at 23°C. Determine the observed van't Hoff factor for this experiment.
1. 1.67
2. 2.73
3. 1.22
4. 0.976
5. 0.002
How many grams of calcium chloride are needed to prepare 300 mL of a 0.250 M solution?
1. 832 g
2. 5.66 g
3. 566 g
4. 112 g
5. 8.32 g
Calculate the osmotic pressure (in torr) of 7.50 liters of an aqueous 0.210 M solution of silver nitrate at 25°C, assuming 100% dissociation.
1. 10.3 torr
2. 7.81 x 10³ torr
3. 0.86 torr
4. 655 torr
5. 1100 torr
Which of the following solutions would be expected to experience the largest deviation from the expected van't Hoff factor?
1. 1.5 M NaCl
2. 0.5 M CH₃OH
3. 1.0 M glucose
4. 0.010 M NaCl
5. Both NaCl solutions would have the same deviation
What is the percentage by mass of ethanol (C₂H₅OH) in a 1.5 m solution?
1. 65%
2. 29%
3. 18.8%
4. 6.5%
5. 0.057%
The rate law for a particular reaction is determined to be R = k[A]²[B]². What is the overall order for this reaction?
1. zero
2. first
3. second
4. third
5. fourth
KClO₃ decomposes according to the reaction:
2KClO₃ → 2KCl + 3O₂
If the rate of decomposition of potassium chlorate at a certain time is determined to be 2.4 x 10^-2 mol s^-1. What is the rate of formation of O₂ at the same time?
1. 2.4 x 10^-2 mol s^-1
2. 1.2 x 10^-2 mol s^-1
3. 3.6 x 10^-2 mol s^-1
4. 7.2 x 10^-2 mol s^-1
5. 1.6 x 10^-2 mol s^-1
For a reaction between X and Y, the following data was obtained:
[X]₀ [Y]₀ Initial Rate
0.10 0.10 2.0 x 10³
0.20 0.10 4.0 x 10³
0.10 0.20 8.0 x 10³
What is the rate law for this reaction?
1. R = k[X][Y]
2. R = k[X]²[Y]²
3. R = k[X][Y]²
4. R = k[X]²[Y]
5. R = k[Y]²
For the following reaction:
A → B + C
that is second order, a linear plot will result when time is plotted against:
1. ln[A]
2. [A]
3. 1/[A]
4. ln[B]
5. ln[B][C]
For a first order reaction with a rate constant k = 1.2 x 10^-3s^-1, how long will it take for the amount of reactant to be decreased from 0.10 mol to 0.05 mol?
1. 580 seconds
2. 6.7 seconds
3. 8.3 x 10³ seconds
4. 8.3 x 10² seconds
5. none of these
For a first order reaction with a rate constant k = 3.13 x 10² s^-1, how long does it take for the concentration of the only reactant to become 40% of the original amount?
1. 0.00128 seconds
2. 0.00293 seconds
3. 0.0450 seconds
4. 0.00479 seconds
5. 43.2 seconds
For a second order reaction with a rate constant k = 3.13 x 10² L mol^-1 s^-1, how long does it take for the concentration of the only reactant to become 70% of the original amount?
1. 0.00137 seconds
2. 0.00746 seconds
3. 0.00114 seconds
4. 0.0761 seconds
5. 0.912 seconds
Catalysts lower the activation energy of a reaction by:
1. adding heat to the reaction system
2. providing an alternate pathway for the reaction
3. increasing the energy content of the reactants
4. changing the value of ΔH for the reaction
5. none of these
The following data give the concentration of gaseous butadiene as a function of time at 500 K. Determine the order of the reaction, and the value of the rate constant.

t(sec) C(moles/liter)
195 1.62 x 10^-2
604 1.47 x 10^-2
1246 1.29 x 10^-2
2180 1.10 x 10^-2
4140 0.89 x 10^-2
4655 0.80 x 10^-2
6210 0.68 x 10^-2
8135 0.57 x 10^-2
1. first order, k = 1.4 x 10² s^-1
2. first order, k = 1.4 x 10^-2 L mol^-1s^-1
3. second order, k = 1.4 x 10^-2 L mol^-1s^-1
4. second order, k = 1.4 x 10² L mol^-1s^-1
5. zero order, k = -1.4 x 10^-2 mol L^-1s^-1
The reaction X₂Y → 2X + Y is determined to be first order. What is the integrated rate law for this reaction?
1. ln[2X + Y] = kt - ln[2X + Y]₀
2. (1/[X₂Y]) = -kt + (1/[X₂Y]₀)
3. [X₂Y] = -kt + [X₂Y]₀
4. ln[X₂Y] = -kt + ln[X₂Y]₀
5. (1/[2X + Y]) = -kt + (1/[2X + Y]₀)
A certain first-order reaction is 50.0% complete in 4.25 minutes. What is the rate constant for this reaction?
1. 0.163 min^-1
2. 2.95 min
3. 6.13 min
4. [A]₀/(2t_1/2)
5. 0.0252 min^-1
A certain first order decomposition reaction reaches 65% completion in 18.9 seconds. What is the rate constant for this reaction?
1. 18 s^-1
2. 19.8 s^-1
3. 9.56 x 10^-2 s^-1
4. 2.38 x 10^-2 s^-1
5. 5.55 x 10^-2 s^-1
The activation energy for the reaction:

X₂(g) + Y₂(g) → 2XY(g)
is 125 kJ/mol and ΔE for the reaction is -45 kJ/mol. The activation energy for the decomposition of XY is:
1. 45 kJ/mol
2. 80 kJ/mol
3. 170 kJ/mol
4. -80 kJ/mol
5. -125 kJ/mol
Increasing the temperature at which a reaction occurs speeds up the reaction by:
1. increasing the frequency of collisions
2. increasing the energy of collisions
3. activating catalysts
4. improving the orientation of collisions
5. two of these
Which of the following statements is TRUE for the catalyzed and uncatalyzed versions of the same reaction?
1. The activation energies are the same
2. The reaction pathway is the same
3. The energy content of the reactants is higher for the uncatalyzed reaction
4. ΔE is the same
5. The energy content of the activated complex is higher for the catalyzed reaction

[X]₀	[Y]₀	Initial Rate
0.10	0.10	2.0 x 10³
0.20	0.10	4.0 x 10³
0.10	0.20	8.0 x 10³

t(sec)	C(moles/liter)
195	1.62 x 10^-2
604	1.47 x 10^-2
1246	1.29 x 10^-2
2180	1.10 x 10^-2
4140	0.89 x 10^-2
4655	0.80 x 10^-2
6210	0.68 x 10^-2
8135	0.57 x 10^-2

Unit 4 Review

Multiple-choice exercise. Twenty questions will be loaded randomly each time you attempt this review activity.