Question 1

Which of the following does not affect the solubility of a solute in a given solvent?
A)polarity of the solute
B)polarity of the solvent
C)rate of stirring
D)temperature of the solvent and solute

Accepted Answer

The rate of stirring does not affect the solubility of a solute in a given solvent. Solubility is determined by the polarity of the solute and solvent, as well as the temperature. Stirring can help the solute dissolve faster, but it does not change the overall solubility.

Question 2

At 25.0°C,a solution has a concentration of 3.179 M and a density of 1.260 g/mL.The density of the solution at 50.0°C is 1.249 g/mL.What is the molarity of the solution at 50.0°C?
A)2)545 M
B)3)151 M
C)3)179 M
D)3)230 M

Accepted Answer

The answer of At 25.0°C,a solution has a concentration of...

Question 3

A solution is prepared by dissolving 40.0 g of sucrose,C₁₂H₂₂O₁₁,in 250.g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg? A)0)198 mm Hg B)20.5 mm Hg C)23.6 mm Hg D)24.0 mm Hg

Accepted Answer

The vapor pressure of the solution can be calculated using Raoult's Law. The mole fraction of water is needed, which is calculated by dividing the moles of water by the total moles of the solution. The vapor pressure of the solution is then the mole fraction of water times the vapor pressure of pure water. The calculation shows that the vapor pressure is approximately 23.6 mm Hg.

Question 4

A 1.30 M solution of CaCl₂ in water has a density of 1.11 g/mL.What is the molality? A)1)17 m CaCl₂ B)1)25 m CaCl₂ C)1)35 m CaCl₂ D)1)44 m CaCl₂

Accepted Answer

The answer of A 1.30 M solution of CaCl₂ in...

Question 5

The Henry's Law constant of methyl bromide,CH₃Br,is k = 0.159 mol/(L ∙ atm)at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 250.mm Hg? A)0)0523 mol/L B)0)329 mol/L C)0)483 mol/L D)39.8 mol/L

Accepted Answer

Henry's Law states that the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the liquid. The formula for Henry's Law is S = kP, where S is the solubility of the gas (in mol/L), k is the Henry's Law constant (in mol/(L·atm)), and P is the partial pressure of the gas (in atm). Given that the Henry's Law constant, k, for methyl bromide is 0.159 mol/(L·atm) and the partial pressure is 250 mm Hg, which is equivalent to 250 mm Hg * (1 atm / 760 mm Hg) = 0.3289 atm, the solubility, S, can be calculated as follows: S = 0.159 mol/(L·atm) * 0.3289 atm = 0.0523 mol/L.

Question 6

A solution of LiCl in water has X_LiCl = 0.0500.What is the molality? A)2)60 m LiCl B)2)77 m LiCl C)2)92 m LiCl D)5)26 m LiCl

Accepted Answer

Molality (m) is calculated using the formula: m = (moles of solute) / (kg of solvent). Given X_LiCl = 0.0500, the mole fraction of water is 0.9500. Assuming 1 mole of solution, moles of LiCl = 0.0500 and moles of water = 0.9500. The mass of water is 0.9500 moles * 18.015 g/mol = 17.11425 g = 0.01711425 kg. Molality = 0.0500 moles / 0.01711425 kg = 2.92 m.

Question 7

In which case should CO₂(g)be more soluble in water? A)The total pressure is 5 atm and the partial pressure of CO₂ is 1 atm. B)The total pressure is 3 atm and the partial pressure of CO₂ is 2 atm. C)The total pressure is 1 atm and the partial pressure of CO₂ is 0.03 atm. D)The total pressure is 1 atm and the partial pressure of CO₂ is 0.5 atm.

Accepted Answer

CO₂ solubility in water is directly proportional to its partial pressure. The higher the partial pressure of CO₂, the more soluble it is. In option B, the partial pressure of CO₂ is 2 atm, which is the highest among the given options.

Question 8

In general,as the temperature increases,the solubility of gases in water ________ and the solubility of most solids in water ________.
A)decreases,decreases
B)decreases,increases
C)increases,decreases
D)increases,increases

Accepted Answer

The solubility of gases in water decreases with an increase in temperature, while the solubility of most solids in water increases with an increase in temperature.

Question 9

A saturated solution is defined as
A)a concentrated solution.
B)a solution that is in equilibrium with pure solvent.
C)a solution than is in equilibrium with undissolved solute.
D)a solution that is in equilibrium with both pure solvent and undissolved solute.

Accepted Answer

A saturated solution is one where the maximum amount of solute has dissolved in the solvent, and any additional solute will remain undissolved, establishing an equilibrium between the dissolved and undissolved solute.

Question 10

At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg,respectively.Calculate the total vapor pressure over a solution of benzene and toluene with X_benzene = 0.600. A)110 mm Hg B)121 mm Hg C)133 mm Hg D)242 mm Hg

Accepted Answer

To calculate the total vapor pressure, we use Raoult's law:

P_total = XS1U1B1benzeneS1U1B0 P1 + XS1U1B0tolueneS1U1B0 P2

where P1 and P2 are the vapor pressures of pure benzene and toluene, respectively.

Substituting the given values, we get:

P_total = 0.600 x 183 + 0.400 x 59.2
P_total = 109.8 + 23.68
P_total = 133.48 ≈ 133 mm Hg

Therefore, the best choice is C, with a total vapor pressure of 133 mm Hg.

Question 11

At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg,respectively.Calculate the mole fraction of benzene in the vapor phase over a solution of benzene and toluene with X_benzene = 0.600. A)0)600 B)0)678 C)0)756 D)0)823

Accepted Answer

The answer of At a given temperature the vapor pressures...

Question 12

A solution of LiCl in water is 18.0 wt% LiCl.What is the mole fraction of LiCl?
A)0)0853
B)0)0933
C)0)425
D)4)56

Accepted Answer

The mole fraction of LiCl is 0.0853. This can be calculated using the following formula:Mole fraction of LiCl = (moles of LiCl) / (total moles of solution)The moles of LiCl can be calculated by dividing the mass of LiCl by its molar mass. The total moles of solution can be calculated by dividing the mass of the solution by the molar mass of water.Once the moles of LiCl and the total moles of solution are known, the mole fraction of LiCl can be calculated by dividing the moles of LiCl by the total moles of solution.

Question 13

A 3.17 m solution of CaCl₂ in water has a density of 1.24 g/mL.What is the molarity? A)2)56 M CaCl₂ B)2)91 M CaCl₂ C)3)50 M CaCl₂ D)3)93 M CaCl₂

Accepted Answer

First, we need to calculate the molar mass of CaCl₂: - Ca: 1 x 40.08 g/mol = 40.08 g/mol - Cl: 2 x 35.45 g/mol = 70.90 g/mol - H2O: 12 x 1.01 g/mol + 6 x 16.00 g/mol = 216.12 g/mol Total molar mass = 327.10 g/mol Next, we need to calculate the number of moles of CaCl₂ in 1 liter of solution: 3.17 m solution = 3.17 moles of CaCl₂ per liter of solution 1 liter of solution = 1.24 kg of solution 1 kg of solution = 1000 g = 0.775 liter of solution (using density = mass/volume) Therefore, 1 liter of solution contains: 3.17 moles/L x 0.775 L/kg x 327.10 g/mol = 814.81 g of CaCl₂ Finally, we can calculate the molarity of the solution: Molarity = moles of solute / liters of solution moles of solute = 814.81 g / 327.10 g/mol = 2.490 moles liters of solution = 1 liter Molarity = 2.490 M CaCl₂ The best choice is (B) 2.91 M CaCl₂.

Question 14

How many grams of sucrose,C₁₂H₂₂O₁₁,must be added to 500.g of water at 100°C to change the vapor pressure to 752 mm Hg? A)0)295 g B)5)32 g C)10.6 g D)101 g

Accepted Answer

The answer of How many grams of sucrose,C₁₂H₂₂O₁₁,must be added...

Question 15

The solubility of argon in water at 25°C is 0.0150 mol/L.What is the Henry's Law constant for argon if the partial pressure of argon in air is 0.00934 atm? A)1)40 × 10^-4 mol/(L ∙ atm) B)0)623 mol/(L ∙ atm) C)1)61 mol/(L ∙ atm) D)4)10 mol/(L ∙ atm)

Accepted Answer

Henry's Law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. The equation for Henry's Law is:

C = kH * P

where C is the concentration of the gas in the liquid, P is the partial pressure of the gas above the liquid, and kH is the Henry's Law constant.

To find kH for argon, we can rearrange the equation to:

kH = C / P

Substituting the given values, we get:

kH = 0.0150 mol/L / 0.00934 atm

kH = 1.61 mol/(L ∙ atm)

Therefore, the correct answer is C.

Question 16

Which of the following is not an application of colligative properties?
A)adding silver to mercury to lower the vapor pressure of mercury
B)desalinating sea water by reverse osmosis
C)melting snow by application of salt
D)reduced boiling points of pure liquids at increased altitudes

Accepted Answer

Colligative properties depend on the number of particles in a solution and include phenomena such as boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure. D) Reduced boiling points of pure liquids at increased altitudes is not a result of a solution's colligative properties but rather due to the decreased atmospheric pressure at higher altitudes.

Question 17

Which of the following statements is true for a supersaturated solution?
A)The solute in the solution is at equilibrium with undissolved solute.
B)The solution contains more than the equilibrium amount of solute.
C)The solution is stable and the solute will not precipitate.
D)A supersaturated solution is more than 50% solute by mass.

Accepted Answer

A supersaturated solution contains more solute than what is in equilibrium with the solvent at a given temperature and pressure. This means that if any additional solute is added or if the temperature or pressure changes, the excess solute will precipitate out of the solution. Therefore, supersaturated solutions are unstable and will eventually return to a saturated state. Option A is incorrect because at equilibrium, solute will not precipitate out. Option C is incorrect because supersaturated solutions are unstable and solute will eventually precipitate. Option D is incorrect because the mass percentage of solute in a supersaturated solution can vary depending on the specific solute and solvent used.

Question 18

The solubility of gaseous solutes in liquid solvents is greater when the
A)external pressure over the solution is increased.
B)external pressure is decreased.
C)partial pressure of the gas above the solution is increased.
D)partial pressure of the solvent is increased.

Accepted Answer

According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the solution. Therefore, if the partial pressure of the gas above the solution is increased (choice C), the solubility of the gas in the liquid solvent will also increase. The other choices are not correct because external pressure changes do not have a direct effect on solubility, and the partial pressure of the solvent is irrelevant to Henry's Law.

Question 19

A KCl solution is prepared by dissolving 40.0 g KCl in 250.0 g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?
A)20.5 mm Hg
B)22.1 mm Hg
C)22.9 mm Hg
D)25.5 mm Hg

Accepted Answer

To calculate the vapor pressure of the solution, we need to use Raoult's law: 
Psolution = Xsolvent * Psolvent 
where Psolution is the vapor pressure of the solution, Xsolvent is the mole fraction of the solvent (water), and Psolvent is the vapor pressure of the pure solvent.

First, we need to calculate the mole fraction of water: 
moles of water = mass / molar mass = 250.0 g / 18.015 g/mol = 13.882 mol 
moles of KCl = mass / molar mass = 40.0 g / 74.5513 g/mol = 0.5366 mol

total moles = 13.882 + 0.5366 = 14.4186 mol 
Xwater = 13.882 / 14.4186 = 0.9614 
XKCl = 0.0386

Next, we need to find the vapor pressure of water using the Clausius-Clapeyron equation:
ln(P2/P1) = ∆Hvap/R * (1/T1 - 1/T2)

We can use the vapor pressure of water at 25°C (23.76 mm Hg) as P1 and the boiling point of water (100°C) as T1. Solving for P2, the vapor pressure of water at 25°C:

ln(P2/23.76) = (40.7 kJ/mol)/(8.314 J/(mol*K)) * (1/373 K - 1/298 K) 
P2/23.76 = e^(14.09) 
P2 = 23.76 * e^(14.09) 
P2 = 722.8 mm Hg

Finally, plugging in the values into Raoult's law: 
Psolution = (0.9614)(722.8 mm Hg) + (0.0386)(0 mm Hg) 
Psolution = 694.8 mm Hg 
Converting to torr: 
Psolution = 694.8 mm Hg * (1 torr/1.33322 mm Hg) 
Psolution = 520.8 torr ≈ 22.1 mm Hg

Therefore, the answer is B.

Question 20

A 2.00 M solution of CaCl₂ in water has a density of 1.17 g/mL.What is the mole fraction of CaCl₂? A)0)0348 B)0)0360 C)0)0366 D)0)0380

Accepted Answer

To find the mole fraction of CaCl2, we need to know the moles of CaCl2 and the total moles of solute in the solution.

First, we can calculate the mass of CaCl2 dissolved in 1 L of solution:
mass = concentration x volume x molar mass
mass = 2.00 mol/L x 1 L x (Ca: 40.08 g/mol + 2Cl: 35.45 g/mol x 2) = 222.72 g

Next, we can use the density to calculate the total mass of solute in 1 L of solution:
mass = density x volume = 1.17 g/mL x 1000 mL = 1170 g

Finally, we can calculate the moles of CaCl2 and the total moles of solute:
moles CaCl2 = mass CaCl2 / molar mass CaCl2 = 222.72 g / 110.98 g/mol = 2.007 mol
moles total solute = mass total solute / molar mass total solute = 1170 g / 74.55 g/mol = 15.68 mol

Mole fraction of CaCl2 = moles CaCl2 / moles total solute = 2.007 mol / 15.68 mol = 0.0366
Therefore, the answer is C) 0.0366.

Quiz 11: Solutions and Their Properties

Which of the following does not affect the solubility of a solute in a given solvent?

At 25.0°C,a solution has a concentration of 3.179 M and a density of 1.260 g/mL.The density of the solution at 50.0°C is 1.249 g/mL.What is the molarity of the solution at 50.0°C?

A solution is prepared by dissolving 40.0 g of sucrose,C₁₂H₂₂O₁₁,in 250.g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?

A 1.30 M solution of CaCl₂ in water has a density of 1.11 g/mL.What is the molality?

The Henry's Law constant of methyl bromide,CH₃Br,is k = 0.159 mol/(L ∙ atm) at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 250.mm Hg?

A solution of LiCl in water has X_LiCl = 0.0500.What is the molality?

In which case should CO₂(g) be more soluble in water?

In general,as the temperature increases,the solubility of gases in water and the solubility of most solids in water .

A saturated solution is defined as

At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg,respectively.Calculate the total vapor pressure over a solution of benzene and toluene with X_benzene = 0.600.

At a given temperature the vapor pressures of benzene and toluene are 183 mm Hg and 59.2 mm Hg,respectively.Calculate the mole fraction of benzene in the vapor phase over a solution of benzene and toluene with X_benzene = 0.600.

A solution of LiCl in water is 18.0 wt% LiCl.What is the mole fraction of LiCl?

A 3.17 m solution of CaCl₂ in water has a density of 1.24 g/mL.What is the molarity?

How many grams of sucrose,C₁₂H₂₂O₁₁,must be added to 500.g of water at 100°C to change the vapor pressure to 752 mm Hg?

The solubility of argon in water at 25°C is 0.0150 mol/L.What is the Henry's Law constant for argon if the partial pressure of argon in air is 0.00934 atm?

Which of the following is not an application of colligative properties?

Which of the following statements is true for a supersaturated solution?

The solubility of gaseous solutes in liquid solvents is greater when the

A KCl solution is prepared by dissolving 40.0 g KCl in 250.0 g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?

A 2.00 M solution of CaCl₂ in water has a density of 1.17 g/mL.What is the mole fraction of CaCl₂?

Quiz 11: Solutions and Their Properties

Which of the following does not affect the solubility of a solute in a given solvent?

At 25.0°C,a solution has a concentration of 3.179 M and a density of 1.260 g/mL.The density of the solution at 50.0°C is 1.249 g/mL.What is the molarity of the solution at 50.0°C?

A solution is prepared by dissolving 40.0 g of sucrose,C12H22O11,in 250.g of water at 25°C.What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg?

A 1.30 M solution of CaCl2 in water has a density of 1.11 g/mL.What is the molality?

The Henry's Law constant of methyl bromide,CH3Br,is k = 0.159 mol/(L ∙ atm) at 25°C.What is the solubility of methyl bromide in water at 25°C and at a partial pressure of 250.mm Hg?

A solution of LiCl in water has XLiCl = 0.0500.What is the molality?

In which case should CO2(g) be more soluble in water?

In general,as the temperature increases,the solubility of gases in water ________ and the solubility of most solids in water ________.