Deck 11: Properties of Solutions-Their Concentrations and Colligative Properties

Question 1

Use the following data to calculate the enthalpy change for the following reaction: 2 Na(s)+ O₂(g) $\to$ Na₂O(s)

A)-1322 kJ/mol
B)-1571 kJ/mol
C)-417 kJ/mol
D)-771 kJ/mol
E)-557 kJ/mol

Answer 1

-417 kJ/mol

Question 2

Which of the following is NOT typically needed to calculate the lattice energy of an ionic compound?

A)enthalpy of vaporization
B)bond enthalpy
C)enthalpy of solution
D)electron affinity
E)ionization energy

Answer 2

enthalpy of solution

Question 3

Create the Born-Haber cycle and calculate the lattice energy of sodium fluoride from the following data: Ionization energy of Na: 496 kJ/mol
Electron affinity of F: -328 kJ/mol
Energy to vaporize Na: 108 kJ/mol
F₂ bond energy: 160 kJ/mol
Energy change for the reaction:
Na(s)+ F₂(g) $\to$ NaF(s); $\Delta$ H = -575 kJ

A)931 kJ/mol
B)-931 kJ/mol
C)-1011 kJ/mol
D)1011 kJ/mol
E)-851 kJ/mol

Answer 3

-931 kJ/mol

Question 4

Which of the following processes is a step in the Born-Haber cycle of NaCl?

A)Na⁺(g)+ Cl^-(g) $\rightarrow$ NaCl(s)
B)Na(s) $\rightarrow$ Na⁺(g)+ e^-
C)Na(g)+ Cl₂(g) $\rightarrow$ NaCl(g)
D) Cl₂(g)+ e ^- $\rightarrow$ Cl ^- (g)
E)Na⁺(aq)+ Cl ^- (aq) $\rightarrow$ NaCl(s)

Question 5

Create the Born-Haber cycle and calculate the lattice energy of lithium chloride (LiCl)from the following data:

A)-603 kJ/mol
B)-11.0 kJ/mol
C)-846 kJ/mol
D)+405 kJ/mol
E)-131 kJ/mol

Question 6

Which of the following will require the greatest energy input to separate the ions?

A)MgI₂
B)MgF₂
C)MgCl₂
D)MgBr₂
E)NaCl

Question 7

Use the following data to calculate the enthalpy change for the following reaction: K(s)+ Cl₂(g) $\to$ KCl(s)

A)-603 kJ/mol
B)-11.0 kJ/mol
C)+405 kJ/mol
D)-318 kJ/mol
E)-438 kJ/mol

Question 8

Which one of the ionic compounds below would you expect to have the highest solubility in water based on its lattice energy?

A)MgF₂
B)CaF₂
C)SrF₂
D)BaF₂
E)BeF₂

Question 9

Which one of the ionic compounds below would you expect to have the smallest (least negative)lattice energy?

A)MgF₂
B)MgCl₂
C)MgBr₂
D)MgI₂
E)CaI₂

Question 10

Which of the following statements regarding the solubility of ionic compounds in water is NOT correct?

A)Ionic compounds containing relatively large ions generally show higher solubility in water.
B)Water can more readily separate and hydrate highly charged ions in ionic solids than ions with smaller charges.
C)Ionic compounds with very large negative lattice energies typically show limited solubility in water.
D)Al₂O₃ is probably less soluble in water than Na₂O in part because its lattice energy is more negative.
E)Ba(OH)₂is probably more soluble in water than Ca(OH)₂ in part because its lattice energy is less negative.

Question 11

Which of the following requires the smallest energy to separate the ions?

A)CaF₂
B)KF
C)NaF
D)MgF₂
E)LiF

Question 12

Which of the following has the largest lattice energy?

A)NaF
B)NaCl
C)NaBr
D)NaI
E)CsCl

Question 13

Which of the following statements regarding the dissolution of ionic compounds in water is NOT correct?

A)Breaking ionic bonds required energy.
B)When ions become hydrated,ion-dipole interactions stabilize the ion in solution.
C)Hydrogen bonding in water is disrupted when water molecules make space for ions in solution.
D)Separating water molecules is an endothermic process.
E)The enthalpy change of solution for ionic compounds is exothermic.

Question 14

Which of the following compounds has the largest lattice energy?

A)NaF
B)KCl
C)RbCl
D)BeF₂
E)NaCl

Question 15

Determine the energy change for the reactio Li(s)+ Cl₂(g) $\to$ LiCl(s)from the following data:
Lattice energy of LiCl = -861 kJ/mol
Energy to vaporize Li = 159 kJ/mol
Ionization energy of Li = 520 kJ/mol
Cl₂ bond energy: 240 kJ/mol
Electron affinity of Cl: -349 kJ/mol

A)-411 kJ/mol
B)-528 kJ/mol
C)311 kJ/mol
D)-861 kJ/mol
E)-291 kJ/mol

Question 16

Coulomb's law states that the interaction energy between ions depends __________

A)only on the ionic charges.
B)only on the distance between the ions.
C)directly on both the ionic charges and the distance between the ions.
D)on the temperature.
E)directly on the ionic charges and inversely on the distance between the ions.

Question 17

Which of the following is needed to calculate the lattice energy of an ionic compound?

A)enthalpy of solution
B)enthalpy of combustion
C)specific heat
D)ionization energy
E)enthalpy of solvation

Question 18

Which one of the ionic compounds below would you expect to have the lowest solubility in water based on its lattice energy?

A)MgO
B)CaO
C)SrO
D)BaO
E)BeO

Question 19

Create the Born-Haber cycle and calculate the lattice energy of lithium oxide (Li₂O)from the following data:

A)-2586 kJ/mol
B)-2972 kJ/mol
C)-3081 kJ/mol
D)-2205 kJ/mol
E)-2831 kJ/mol

Question 20

Which one of the ionic compounds below would you expect to have the largest (most negative)lattice energy?

A)MgF₂
B)MgCl₂
C)MgBr₂
D)MgI₂
E)CaI₂

Question 21

Which statement below regarding the liquid-gas phase transition and boiling is NOT correct?

A)More molecules have sufficient energy to escape the liquid phase at higher temperatures.
B)The vapor pressure of a liquid increases with temperature.
C)Boiling occurs when the vapor pressure of a liquid equals 1 standard atm.
D)More volatile liquids have lower boiling points.
E)Liquids with stronger intermolecular forces typically have higher boiling points.

Question 22

Which of the following statements regarding the solubility of molecular compounds in water is NOT correct?

A)Energy is required to overcome solute-solute interactions.
B)Making room for the solute between solvent molecules is endothermic.
C)Heats of solution near zero mean that the intermolecular forces between the solute and solvent are not sufficient to overcome the solute-solute and solvent-solvent attractive forces.
D)Negative heats of solution mean that solute-solvent intermolecular attractions are stronger than those in the pure solute and pure solvent.
E)Similar types and strengths of intermolecular forces often lead to higher solubility than dissimilar ones.

Question 23

Lanterns and stoves that use n-pentane as a fuel are often difficult to light on a cold day because the fuel has a low vapor pressure at low temperatures.Determine the vapor pressure of n-pentane on a night when the temperature is 0.0 ^$\circ$ C.The enthalpy of vaporization of n-pentane is 27.6 kJ/mol,and its boiling point is 36.0 ^$\circ$ C.

A)228 torr
B)367 torr
C)185 torr
D)479 torr
E)209 torr

Question 24

What physical property is used to separate the hydrocarbon components in petroleum (crude oil)?

A)melting point
B)density
C)boiling point
D)molar mass
E)viscosity

Question 25

Which of the solutions shown here will have the lowest vapor pressure? White circles indicate solvent molecules; black circles indicate molecules of a nonvolatile solute.

A)

B)

C)

D)

E)all are equivalent

Question 26

Based on lattice energies,which of the following ranks the compounds from highest to lowest solubility in water?

A)NaF > MgF₂ > CaF₂ > KF
B)KF > NaF > CaF₂ > MgF₂
C)MgF₂ > CaF₂ > NaF > KF
D)CaF₂ > KF > NaF > MgF₂
E)MgF₂ > CaF₂ > KF > NaF

Question 27

Which statement regarding the fractional distillation of two liquids is NOT correct?

A)The substance with the lower boiling point has a higher concentration in the vapor than in the liquid.
B)The boiling point of the mixture is not constant,changing as the distillation progresses.
C)The substance with the higher vapor pressure has a higher concentration in the vapor than in the liquid.
D)The mole ratio of the two substances in the vapor is not the same as it is in the liquid.
E)Raoult's law does not apply to mixtures of volatile components.

Question 28

Based on lattice energies,which listing do you predict is in order of decreasing solubility in water?

A)NaF > MgF₂ > AlF₃
B)MgF₂ > NaF > AlF₃
C)AlF₃ > MgF₂ > NaF
D)AlF₃ > NaF > MgF₂
E)NaF > AlF₃ > MgF₂

Question 29

The normal boiling point of ammonia is -33.34 ^$\circ$ C,and its enthalpy of vaporization is 23.35 kJ/mol.What pressure would have to be applied for ammonia to boil at 25.00 ^$\circ$ C?

A)9.891 atm
B)0.09626 atm
C)0.9037 atm
D)1.268 atm
E)10.39 atm

Question 30

Which statement below regarding evaporation and condensation of a liquid in a closed container is NOT correct?

A)When a liquid is first placed in a closed container,the evaporation rate is higher than it is in an open container under the same conditions.
B)When a liquid is first placed in a closed container,the evaporation rate is higher than the condensation rate.
C)When the rates of evaporation and condensation are equal,the system has reached dynamic equilibrium.
D)Vapor pressure refers to the pressure of a gas at a given temperature in equilibrium with its liquid phase.
E)Stronger intermolecular forces within the liquid typically result in a lower vapor pressure under a given set of conditions.

Question 31

Gasoline is primarily a mixture of hydrocarbons and is sold with an octane rating that is based on a comparison with the properties of isooctane (C₈H₁₈),which has an enthalpy of vaporization of 35.8 kJ/mol and a normal boiling point of 98.2 ^$\circ$ C.Determine the vapor pressure of isooctane on a very hot day when the temperature is 38.0 ^$\circ$ C.

A)80.6 torr
B)36.7 torr
C)67.8 torr
D)47.9 torr
E)89.3 torr

Question 32

Which statement regarding the boiling of a mixture of liquids A and B is NOT correct?

A)The distillate collected boils at lower temperatures as the percentage of A increases.
B)The distillate always contains a higher percentage of B because pure B is less volatile than pure A.
C)The upper curve reflects the composition of the vapor at a given temperature.
D)As the distillation progresses from point 2 to point 6,the liquid becomes richer in A.
E)The boiling point of pure A is lower than that of pure B.

Question 33

The normal boiling point of benzene is 80.1 ^$\circ$ C,and its enthalpy of vaporization is 30.76 kJ/mol.What is the approximate vapor pressure of benzene at 30.0 ^$\circ$ C?

A)0.998 atm
B)0.926 atm
C)0.839 atm
D)0.177 atm
E)5.65 atm

Question 34

Acetone is a fairly volatile liquid with a vapor pressure of 0.299 atm at 25.0 ^$\circ$ C,and its normal boiling point is 56.5 ^$\circ$ C.Calculate an estimate of acetone's enthalpy of vaporization in kJ/mol.

A)"-31.3 kJ/mol"
B)"+31.3 kJ/mol"
C)"+309 kJ/mol"
D)"+13.6 kJ/mol"
E)"-13.6 kJ/mol"

Question 35

Which statement below regarding vapor pressure is NOT correct?

A)Vapor pressure is an intensive property.
B)The substance with the stronger intermolecular forces has the lower vapor pressure.
C)Vapor pressure increases with increasing temperature.
D)Pure water has a higher vapor pressure at a given temperature than seawater.
E)A nonvolatile solute increases the vapor pressure of the solvent.

Question 36

The aroma from almonds and cherries is due in part to a compound called benzaldehyde.A graph of the natural logarithm of the vapor pressure of benzaldehyde vs.1/temperature produces a straight line with a slope of -5870.99 K.What is the enthalpy of vaporization of benzaldehyde?

A)+473 kJ/mol
B)-47.3 kJ/mol
C)+47.3 kJ/mol
D)-48.8 kJ/mol
E)+48.8 kJ/mol

Question 37

Gasoline is primarily a mixture of hydrocarbons and is sold with an octane rating that is based on a comparison with the combustion properties of isooctane.Gasoline usually contains an isomer of isooctane called tetramethylbutane (C₈H₁₈),which has an enthalpy of vaporization of 43.3 kJ/mol and a boiling point of 106.5 ^$\circ$ C.Determine the vapor pressure of tetramethylbutane on a very hot day when the temperature is 38.0 ^$\circ$ C.

A)80.0 torr
B)37.1 torr
C)67.8 torr
D)47.9 torr
E)89.3 torr

Question 38

Which of the solutions shown here will have the highest vapor pressure? White circles indicate solvent molecules; black circles indicate molecules of a nonvolatile solute.

A)

B)

C)

D)

E)all are equivalent

Question 39

Which statement below regarding evaporation is NOT correct?

A)A liquid in an open container will evaporate because some molecules will have enough kinetic energy to escape into the vapor phase.
B)Stronger intermolecular forces enable more molecules to escape from the liquid phase into the vapor phase.
C)Higher temperatures promote higher evaporation rates because more molecules have enough kinetic energy to escape into the vapor phase.
D)A solid can have a vapor pressure just as a liquid does.
E)Potential energy changes accompany kinetic energy changes when a liquid evaporates.

Question 40

The smell of fresh-cut pine is due in part to a cyclic alkene called pinene.A graph of the natural logarithm of the vapor pressure of pinene vs.1/temperature produces a straight line with a slope of -4936.37 K.What is the enthalpy of vaporization of pinene?

A)+397 kJ/mol
B)-39.7 kJ/mol
C)+39.7 kJ/mol
D)-41.0 kJ/mol
E)+41.0 kJ/mol

Question 41

A solution is prepared by mixing 50.00 g of methanol (CH₃OH,32.04 g/mol)with 50.00 g of ethanol (CH₃CH₂OH,46.07 g/mol).Use the following data to determine the vapor pressure of this solution at 20 ^$\circ$ C.

A)69 torr
B)57 torr
C)79 torr
D)73 torr
E)83 torr

Question 42

A solution is prepared by mixing 45.68 of carbon disulfide (CS₂,76.13 g/mol)with 16.42 g of acetonitrile (CH₃CN,41.06 g/mol).What is the vapor pressure of the solution at 25 ^$\circ$ C? Substance

A)3.57 $\times$ 10² torr
B)2.50 $\times$ 10² torr
C)2.14 $\times$ 10² torr
D)1.97 $\times$ 10² torr
E)8.95 $\times$ 10¹ torr

Question 43

You wish to prepare a solution of methanol (CH₃OH,32.04 g/mol)and ethanol (CH₃CH₂OH,46.07 g/mol)that has a total vapor pressure of 66 torr at 20 ^$\circ$ C.Calculate the mole fraction of ethanol in the solution that will produce the desired pressure.

A)0.55
B)0.68
C)0.48
D)0.72
E)0.38

Question 44

A solution is prepared by mixing 45.68 g of carbon disulfide (CS₂,76.13 g/mol)with 16.42 g of acetonitrile (CH₃CN,41.06 g/mol).What is the partial pressure of CS₂ in the vapor phase at 25 ^$\circ$ C?

A)3.57 $\times$ 10² torr
B)2.50 $\times$ 10² torr
C)2.14 $\times$ 10² torr
D)1.97 $\times$ 10² torr
E)8.95 $\times$ 10¹ torr

Question 45

Which of the following regarding the vapor pressure of a solution containing a nonvolatile solute is NOT correct?

A)The amount by which the vapor pressure of the solution is reduced reflects the mole fraction of the solute in the solution.
B)Raoult's law predicts that a solution containing a solute that experiences strong solute-solvent attractions will have a lower vapor pressure than an ideal solution.
C)The presence of a nonvolatile solute reduces the mole fraction of the pure solvent.
D)The evaporation rate of the pure solvent in an open container is higher than that of the solution.
E)The condensation rates of the pure solvent and the solution are probably about equal.

Question 46

A solution is prepared by adding 0.300 mol glucose,which is not volatile,to 4.50 mol water.What is the vapor pressure of this solution at 25 ^$\circ$ C given that the vapor pressure of pure water is 23.8 torr?

A)9.38 torr
B)1.49 torr
C)23.4 torr
D)22.3 torr
E)22.5 torr

Question 47

A solution is prepared by mixing 75 g of methanol (CH₃OH,32.04 g/mol)with 25 g of ethanol (CH₃CH₂OH,46.07 g/mol).What is the mole fraction of ethanol in the vapor phase at 20 ^$\circ$ C?

A)0.10
B)0.12
C)0.19
D)0.32
E)0.54

Question 48

A solution is prepared by adding 1.50 mol glucose,which is not volatile,to 3.50 mol water.What is the vapor pressure of this solution at 25 ^$\circ$ C given that the vapor pressure of pure water is 23.8 torr?

A)7.00 torr
B)16.7 torr
C)10.2 torr
D)7.14 torr
E)34.0 torr

Question 49

Which statement regarding nonideal solutions is NOT correct?

A)The boiling point of a nonideal solution is higher than that of an ideal solution.
B)Ideal solutions follow Raoult's law,where the total vapor pressure is the sum of the mole fractions of the volatile components multiplied by their vapor pressure when they are pure P_total = x₁P₁ + x₂P₂ + …).
C)When adhesive forces are stronger than cohesive forces in the solution,negative deviations from Raoult's law are observed.
D)Positive deviations from Raoult's law are observed when solute-solute and solvent-solvent interactions are stronger than solute-solvent attractions.
E)Raoult's law does not apply to mixtures of volatile components.

Question 50

A solution is prepared by mixing 75 g of methanol (CH₃OH,32.04 g/mol)with 25 g of ethanol (CH₃CH₂OH,46.07 g/mol).What is the partial pressure of methanol in the vapor phase at 20 ^$\circ$ C?

A)92 torr
B)83 torr
C)75 torr
D)55 torr
E)45 torr

Question 51

You must use 168 g of carbon disulfide (CS₂,76.13 g/mol)with acetonitrile (CH₃CN,41.06 g/mol)to create a solution that has a total vapor pressure of 292 torr at 25 ^$\circ$ C.Calculate the number of grams of CH₃CN required.

A)40.6 g
B)29.1 g
C)90.6 g
D)42.1 g
E)4.93 g

Question 52

What is the vapor pressure of an aqueous solution that has a solute mole fraction of $\chi$ = 0.100? The vapor pressure of water is 25.756 mmHg at 25 ^$\circ$ C.

A)23.2 mmHg
B)2.58 mmHg
C)25.8 mmHg
D)0.900 mmHg
E)22.3 mmHg

Question 53

Which of the following regarding colligative properties of a solution is NOT correct?

A)Colligative properties depend on the concentration of the particles dissolved in the solvent.
B)Vapor pressure reduction is a colligative property.
C)The temperature range over which a solution remains liquid is larger than that of the pure solvent arises due to the presence of solute particles.
D)The change in the boiling point of a solvent due to the presence of a solute is a colligative property.
E)The freezing point of a solution increases as the concentration of solute increases.

Question 54

Which of the following pairs of liquids probably exhibits very nearly ideal behavior when mixed?

A)CH₃NH₂ and H₂O
B)CH₃CN and H₂O
C)CH₃Br and CH₃OCH₃
D)CH₃CH₂OH and CH₃COOH
E)C₇H₁₆ and C₈H₁₈

Question 55

A solution contains 6.50 mol water,0.300 mol sucrose,and 0.200 mol glucose.The solutes are nonvolatile.What is the vapor pressure of the solution at 35 ^$\circ$ C given that the vapor pressure of water is 42.2 torr?

A)35.0 torr
B)36.0 torr
C)37.0 torr
D)39.2 torr
E)39.0 torr

Question 56

A solution is prepared by mixing 45.68 g of carbon disulfide (CS₂,76.13 g/mol)with 16.42 g of acetonitrile (CH₃CN,41.06 g/mol).What is the mole fraction of CS₂ in the vapor phase at 25 ^$\circ$ C?

A)1.00
B)0.600
C)0.167
D)0.273
E)0.857

Question 57

A solution is prepared by mixing 75 g of methanol (CH₃OH,32.04 g/mol)with 25 g of ethanol (CH₃CH₂OH,46.07 g/mol).Use the following data to determine the vapor pressure of this solution at 20 ^$\circ$ C.

A)69 torr
B)57 torr
C)80 torr
D)73 torr
E)83 torr

Question 58

Which of the following pairs of liquids probably exhibits positive deviations from Raoult's law when mixed?

A)CH₃OH and H₂O
B)C₆H₁₄ and C₆H₆
C)CH₃Br and H₂O
D)CH₃CH₂OH and CH₃COOH
E)C₇H₁₆ and C₈H₁₈

Question 59

A solution is prepared by mixing 3.50 mL dichloromethane (CH₂Cl₂,84.93 g/mol,1.33 g/mL)with 3.50 mL dibromomethane (CH₂Br₂,173.8 g/mol,2.48 g/mL).By what factor is the vapor phase enriched in CH₂Cl₂ at 25 ^$\circ$ C?

A)35.3
B)10.8
C)2.06
D)1.77
E)11.7

Question 60

A solution is prepared by mixing 45.68 g of carbon disulfide (CS₂,76.13 g/mol)with 16.43 g of acetonitrile (CH₃CN,41.06 g/mol).By what factor is the vapor phase enriched in CS₂ at 25 ^$\circ$ C?

A)8.97
B)1.67
C)5.99
D)3.99
E)1.47

Question 61

A solution is prepared by dissolving 0.330 moles of naphthalene (C₁₀H₈,128.2 g/mol)in 0.500 kg hexane (C₆H₁₄,86.20 g/mol).How many grams of the solution contain 0.150 mol naphthalene?

A)247 g
B)239 g
C)440.0 g
D)493 g
E)4450 g

Question 62

At 25 ^$\circ$ C,the vapor pressure of pure water is 25.756 mmHg.Starting with 250.0 g water and solid glucose (C₆H₁₂O₆,180.2 g/mol),you must create an aqueous solution that has a vapor pressure reduction of 2.000 mmHg.How many grams of glucose do you need?

A)1.17 g
B)14.1 g
C)19.5 g
D)166 g
E)211 g

Question 63

The vapor pressure of an aqueous solution is found to be 24.9 mmHg at 25 ^$\circ$ C.What is the mole fraction of solute in this solution? The vapor pressure of water is 25.756 mmHg at 25 ^$\circ$ C.

A)0.967
B)0.033
C)1.03
D)0.034
E)0.976

Question 64

The normal temperature range of the liquid phase of pure water is 0 ^$\circ$ C to 100 ^$\circ$ C.Which of the following solutions will have the largest temperature range for the liquid state?

A)1 M aqueous ethanol solution
B)1 M aqueous potassium bromide solution
C)1 M aqueous acetic acid solution
D)1 M aqueous magnesium bromide solution
E)1 M aqueous magnesium sulfate

Question 65

What is the molality of a lithium chloride solution produced by dissolving 14.40 g of LiCl (42.39 g/mol)in water to make 0.104 L of solution with a density of 1.102 g/mL?

A)0.340 m
B)3.39 m
C)3.27 m
D)3.74 m
E)2.96 m

Question 66

Calculate the molality of a solution containing 0.755 mol glucose (C₆H₁₂O₆)and 1750 g of water.

A)0.875 m
B)0.583 m
C)0.431 m
D)580 m
E)0.850 m

Question 67

Calculate the molality of a solution containing 0.355 mol sucrose (C₁₂H₂₂O₁₁)and 245 g of water.

A)1.12 $\times$ 10^-2 m
B)1.45 m
C)2.11 m
D)1.12 $\times$ 10^-3 m
E)0.0211 m

Question 68

At 25 ^$\circ$ C,the vapor pressure of pure water is 25.756 mmHg.What is the vapor pressure of water in a solution that contains 2.922 g of sodium chloride for every 100.0 g of water?

A)0.4602 mmHg
B)0.2301 mmHg
C)25.52 mmHg
D)25.35 mmHg
E)12.88 mmHg

Question 69

The vapor pressure of benzene (C₆H₆,78.12 g/mol)at 25 ^$\circ$ C is 0.1252 atm.What is the change in the vapor pressure when 10.00 g naphthalene (C₁₀H₈,128.2 g/mol)is dissolved in 0.2000 kg C₆H₆?

A)"-0.9704 atm"
B)"-0.0296 atm"
C)"-0.0036 atm"
D)"-0.1215 atm"
E)"-0.97040 atm"

Question 70

A 4.028 m aqueous ethylene glycol (C₂H₆O₂,62.07 g/mol)solution has a density of about 1.024 g/mL at 20 ^$\circ$ C.How many mL of solution contain 25.0 g C₂H₆O₂?

A)2.44 $\times$ 10¹ mL
B)1.00 $\times$ 10² mL
C)1.02 $\times$ 10² mL
D)1.22 $\times$ 10² mL
E)1.25 $\times$ 10² mL

Question 71

Indicate which aqueous solution has the fastest evaporation rate.

A)0.1 M KCl
B)0.2 M Na₂CO₃
C)0.2 M NaCl
D)0.1 M MgCl₂
E)0.2 M MgCl₂

Question 72

How many moles of solute are there in a 0.155 m glucose (C₆H₁₂O₆)solution prepared with 50.0 kg of water?

A)15.5 mol
B)15.0 mol
C)0.155 mol
D)31.0 mol
E)7.75 mol

Question 73

Which of the following statements regarding the phase diagram of water and an aqueous solution is NOT correct? Temperature is on the x-axis; pressure,on the y-axis.

A)The boiling point of the solution is higher than that of the solvent by an amount indicated by the difference in temperature between points E and F.
B)Point D corresponds to the triple point of the solvent.
C)The solution boils at the temperature corresponding to point F.
D)The normal freezing point of the solution corresponds to point A.
E)The freezing point of the solvent is higher than that of the solution.

Question 74

What is the boiling point of a solution prepared by dissolving 60.00 grams of sorbitol (C₆H₁₄O₆,182.2 g/mol)in 240.0 grams of water? (K_b = 0.512 ^$\circ$ C/m for water)

A)99.3 ^$\circ$ C
B)100.1 ^$\circ$ C
C)100.4 ^$\circ$ C
D)101.4 ^$\circ$ C
E)100.7 ^$\circ$ C

Question 75

Indicate which aqueous solution has the lowest vapor pressure.

A)0.1 M KCl
B)0.1 M Na₂CO₃
C)0.2 M NaCl
D)0.1 M MgCl₂
E)0.2 M MgCl₂

Question 76

The concentration unit of molality is symbolized as

A)M
B)m
C)(M)
D)mol
E)mo

Question 77

Indicate which aqueous solution has the highest vapor pressure.

A)0.1 M KCl
B)0.2 M Na₂CO₃
C)0.2 M NaCl
D)0.1 M MgCl₂
E)0.2 M MgCl₂

Question 78

What is the boiling point elevation constant of ethanol if a solution prepared by dissolving 56.00 g glycerin (C₃H₈O₃,92.11 g/mol)in 240.0 g ethanol (C₂H₆O,46.08 g/mol)has a boiling point change of 3.014 ^$\circ$ C.

A)1.029 ^$\circ$ C/m
B)0.6080 ^$\circ$ C/m
C)1.190 ^$\circ$ C/m
D)0.8405 ^$\circ$ C/m
E)0.4398 ^$\circ$ C/m

Question 79

What is the boiling point of a solution prepared by dissolving 10.00 grams of naphthalene (C₁₀H₈,128.2 g/mol)in 200.0 grams of benzene (C₆H₆,78.12 g/mol)? The normal boiling point of benzene is 80.1 ^$\circ$ C and K_b = 2.53 ^$\circ$ C/m.

A)79.1 ^$\circ$ C
B)81.1 ^$\circ$ C
C)80.5 ^$\circ$ C
D)86.6 ^$\circ$ C
E)101.0 ^$\circ$ C

Question 80

Indicate which aqueous solution has the slowest evaporation rate.

A)0.1 M KCl
B)0.2 M Na₂CO₃
C)0.2 M NaCl
D)0.1 M MgCl₂
E)0.1 M NaBr