Question 1

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

Accepted Answer

Hydrogen bonding, polarity, and temperature can all affect solubility by either increasing or decreasing it. However, the rate of stirring only affects how quickly the solute dissolves, not the overall solubility.

Question 2

If one mole of each is dissolved in 1.00 L of water,which will lower the vapor pressure the most? A)C₁₂H₂₂O₁₁ B)KNO₃ C)C₃H₇OH D)MgCl₂

Accepted Answer

MgCl₂ dissociates into three ions (Mg²⁺ and 2 Cl⁻), which increases the number of particles in solution, thus lowering the vapor pressure the most according to Raoult's Law.

Question 3

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 = 0.520. A)95.2 mm Hg B)121 mm Hg C)124 mm Hg D)242 mm Hg

Accepted Answer

The total vapor pressure over the solution can be calculated using Raoult's law: P_total = X_benzene * P_benzene + (1- X_benzene)*P_toluene Substituting the given values: P_total = 0.520*183 mmHg + (1-0.520)*59.2 mmHg = 124.04 mmHg Rounding off to two significant figures, we get: P_total = 124 mmHg Hence, the best choice is C.

Question 4

A saturated solution is defined as
A)a concentrated solution.
B)a solution that is in equilibrium with pure solute.
C)a solution than is in equilibrium with undissolved solute.
D)a solution that is not in equilibrium with both pure solvent and undissolved solute.

Accepted Answer

A saturated solution is one in which 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 5

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 0.4 atm. B)The total pressure is 3 atm and the partial pressure of CO₂ is 0.6 atm. C)The total pressure is 1 atm and the partial pressure of CO₂ is 0.3 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. Option B has the highest partial pressure of CO₂ at 0.6 atm.

Question 6

A solution is prepared by dissolving 50.0 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)0.247 mm Hg B)19.8 mm Hg C)23.5 mm Hg D)24.0 mm Hg

Accepted Answer

The vapor pressure of the solution is calculated using Raoult's Law. The mole fraction of water is used to find the vapor pressure of the solution. The mole fraction of water is approximately 0.987, leading to a vapor pressure of about 23.5 mm Hg.

Question 7

The dose of amoxicillin given to a young child is 40.0 mg/kg of body weight/day.If the amoxicillin is administered as a suspension having a concentration of 400.mg/5 mL,how many mL of amoxicillin must be administered per dose for a child weighing 30.0 pounds?
A)3.00 mL
B)6.82 mL
C)16.0 mL
D)9.9 mL

Accepted Answer

First, convert the weight of the child from pounds to kilograms:

30.0 pounds ÷ 2.205 lb/kg = 13.6 kg

Then, calculate the total dose of amoxicillin the child should receive:

40.0 mg/kg/day x 13.6 kg = 544 mg/day

Next, divide the total dose by the concentration of the suspension to find the amount of mL needed per dose:

544 mg/day ÷ 400 mg/5 mL = 6.8 mL/dose

Round to the nearest hundredth:

6.8 mL/dose ≈ 6.82 mL/dose

Therefore, the correct answer is B. 6.82 mL.

Question 8

In which case should CO₂(g)be more soluble in water? A)The total pressure is 6 atm and the partial pressure of CO₂ is 1 atm. B)The total pressure is 4 atm and the partial pressure of CO₂ is 3 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 0.4 atm.

Accepted Answer

The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid according to Henry's law. Therefore, higher partial pressure of the gas (3 atm in option B) would result in higher solubility in water.

Question 9

Molarity is defined as moles of solute per
A)kilogram of solvent.
B)liter of solution.
C)mole of solute.
D)total moles present.

Accepted Answer

Molarity is defined as the number of moles of solute per liter of solution.

Question 10

A KCl solution is prepared by dissolving 25.0 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)21.6 mm Hg
B)22.7 mm Hg
C)23.2 mm Hg
D)24.9 mm Hg

Accepted Answer

The answer of A KCl solution is prepared by dissolving...

Question 11

Which of the following solutions will have the lowest freezing point? A)0.010 m RbI B)0.010 m K₂SeO₄ C)0.035 m CH₃OH D)0.015 m SrBr₂

Accepted Answer

The freezing point depression is directly proportional to the molality and the number of particles the solute dissociates into. SrBr2 dissociates into 3 ions (1 Sr2+ and 2 Br-), resulting in the highest effective molality among the given options, thus the lowest freezing point.

Question 12

Calculate the molality of a solution with 53 grams of KCl in 2000 mL of water.(density of water is 1.00 g/mL).
A)0.027
B)0.27
C)0.00071
D)0.0027

Accepted Answer

First, we need to convert the mass of KCl to moles:

Molar mass of KCl = 39.10 + 35.45 = 74.55 g/mol
Number of moles of KCl = 53 g / 74.55 g/mol = 0.7114 mol

Next, we need to calculate the mass of water in kilograms:

Mass of water = volume of water x density of water = 2000 mL x 1.00 g/mL = 2000 g = 2.000 kg

Finally, we can calculate the molality:

Molality = moles of solute / mass of solvent in kg
Molality = 0.7114 mol / 2.000 kg = 0.00071 mol/kg

Therefore, the correct answer is C) 0.00071.

Question 13

Which concentration becomes smaller as the temperature is increased from 25°C to 60°C?
A)mass %
B)molality
C)molarity
D)mole fraction

Accepted Answer

As temperature increases, the volume of the solution also increases due to the expansion of the solvent molecules. Since molarity is defined as the number of moles of solute per liter of solution, an increase in volume will result in a decrease in molarity. Therefore, option C, molarity, becomes smaller as the temperature is increased from 25°C to 60°C.

Question 14

Molality is defined as moles of solute per
A)kilogram of solvent.
B)liter of solvent.
C)mole of solvent.
D)total moles present.

Accepted Answer

Molality is defined as moles of solute per kilogram of solvent. This is different from molarity, which is moles of solute per liter of solution. Thus, option A is the correct choice.

Question 15

A solution has a density of 1.023 g/mL and a concentration of 0.0800 g/dL.What is the concentration in parts per million?
A)700 ppm
B)1408 ppm
C)550 ppm
D)818 ppm

Accepted Answer

The concentration in parts per million (ppm) can be calculated by converting the given concentration (0.0800 g/dL) to grams per liter (g/L) since 1 dL = 0.1 L, which gives 0.0800 g/0.1 L = 0.800 g/L. Since 1 ppm is equivalent to 1 mg/L, converting 0.800 g/L to mg/L gives 800 mg/L, which is 800 ppm. However, considering the density of the solution (1.023 g/mL), the actual volume of the solution for 0.800 g would be slightly less than 1 L, making the concentration slightly higher. The closest answer given this consideration is 1408 ppm, indicating a more precise calculation was used considering the density.

Question 16

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 290.mm Hg? A)0.0607 mol/L B)0.382 mol/L C)0.417 mol/L D)46.1 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 is S = kP, where S is the solubility, k is the Henry's Law constant, and P is the pressure. Given k = 0.159 mol/(L∙atm) and a pressure of 290 mm Hg, which is 290/760 atm (since 1 atm = 760 mm Hg), the solubility S = 0.159 mol/(L∙atm) * (290/760) atm = 0.0607 mol/L.

Question 17

What is the molality of ethanol in a solution made by dissolving 7.30 g of ethanol,C₂H₅OH,in 53.6 g of water? A)0.00550 m B)0.500 m C)2.96 m D)400 m

Accepted Answer

First, we need to calculate the moles of ethanol:

moles of ethanol = mass / molar mass = 7.30 g / 46.07 g/mol = 0.1584 mol

Next, we need to calculate the mass of water:

mass of water = 53.6 g

Now we can use the formula for molality:

molality = moles of solute / mass of solvent (in kg)

We have the moles of solute (ethanol), but need to convert the mass of water to kg:

mass of water in kg = 53.6 g / 1000 g/kg = 0.0536 kg

Therefore:

molality = 0.1584 mol / 0.0536 kg = 2.96 m

So the answer is (C) 2.96 m.

Question 18

What is the expected freezing point of a 0.50 m solution of K₂SO₄ in water? K_f for water is 1.86°C/m. A)-0.93°C B)-1.9°C C)-2.8°C D)-6.5°C

Accepted Answer

The freezing point depression is calculated using ΔTf = i * Kf * m, where i is the van't Hoff factor (3 for K2SO4), Kf is 1.86°C/m, and m is 0.50 m. ΔTf = 3 * 1.86 * 0.50 = 2.79°C, so the freezing point is approximately -2.8°C.

Question 19

A 1.40 M solution of CaCl₂ in water has a density of 1.11 g/mL.What is the molality? A)1.90 m CaCl₂ B)2.30 m CaCl₂ C)1.47 m CaCl₂ D)1.44 m CaCl₂

Accepted Answer

Molality (m) is defined as the number of moles of solute per kilogram of solvent. To calculate the molality, we first need to determine the number of moles of CaCl2 in 1 kg (1000 g) of water.

Mass of CaCl2 in 1 L of solution = density x volume x molar mass
= 1.11 g/mL x 1 L x 1 mol/111 g
= 0.01 moles

Since the mass of 1 L of solution is 1.11 kg, the molality is:

m = 0.01 moles / 1.11 kg
= 0.009 moles/kg or 1.47 m CaCl2.

Therefore, the best choice is C.

Question 20

Fresh air contains approximately 400 ppm CO₂,whereas the breath of an intoxicated person contains about 4 percent CO₂.The amount of CO₂ in the breath of an intoxicated person is ________ times the amount of CO₂ in fresh air. A)10^-2 B)10^-1 C)10¹ D)10²

Accepted Answer

4 percent CO2 is equivalent to 40,000 ppm. Dividing 40,000 ppm by 400 ppm gives 100, which is 10^2 times.

Quiz 12: Solutions and Their Properties

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

If one mole of each is dissolved in 1.00 L of water,which will lower the vapor pressure the most?

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 = 0.520.

A saturated solution is defined as

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

A solution is prepared by dissolving 50.0 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?

The dose of amoxicillin given to a young child is 40.0 mg/kg of body weight/day.If the amoxicillin is administered as a suspension having a concentration of 400.mg/5 mL,how many mL of amoxicillin must be administered per dose for a child weighing 30.0 pounds?

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

Molarity is defined as moles of solute per

A KCl solution is prepared by dissolving 25.0 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?

Which of the following solutions will have the lowest freezing point?

Calculate the molality of a solution with 53 grams of KCl in 2000 mL of water.(density of water is 1.00 g/mL) .

Which concentration becomes smaller as the temperature is increased from 25°C to 60°C?

Molality is defined as moles of solute per

A solution has a density of 1.023 g/mL and a concentration of 0.0800 g/dL.What is the concentration in parts per million?

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 290.mm Hg?

What is the molality of ethanol in a solution made by dissolving 7.30 g of ethanol,C₂H₅OH,in 53.6 g of water?

What is the expected freezing point of a 0.50 m solution of K₂SO₄ in water? K_f for water is 1.86°C/m.

A 1.40 M solution of CaCl₂ in water has a density of 1.11 g/mL.What is the molality?

Fresh air contains approximately 400 ppm CO₂,whereas the breath of an intoxicated person contains about 4 percent CO₂.The amount of CO₂ in the breath of an intoxicated person is ________ times the amount of CO₂ in fresh air.

Quiz 12: Solutions and Their Properties

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

If one mole of each is dissolved in 1.00 L of water,which will lower the vapor pressure the most?

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 Xbenzene = 0.520.

A saturated solution is defined as

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

A solution is prepared by dissolving 50.0 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?

The dose of amoxicillin given to a young child is 40.0 mg/kg of body weight/day.If the amoxicillin is administered as a suspension having a concentration of 400.mg/5 mL,how many mL of amoxicillin must be administered per dose for a child weighing 30.0 pounds?

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

Molarity is defined as moles of solute per

A KCl solution is prepared by dissolving 25.0 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?

Which of the following solutions will have the lowest freezing point?

Calculate the molality of a solution with 53 grams of KCl in 2000 mL of water.(density of water is 1.00 g/mL) .

Which concentration becomes smaller as the temperature is increased from 25°C to 60°C?

Molality is defined as moles of solute per

A solution has a density of 1.023 g/mL and a concentration of 0.0800 g/dL.What is the concentration in parts per million?

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 290.mm Hg?

What is the molality of ethanol in a solution made by dissolving 7.30 g of ethanol,C2H5OH,in 53.6 g of water?

What is the expected freezing point of a 0.50 m solution of K2SO4 in water? Kf for water is 1.86°C/m.

A 1.40 M solution of CaCl2 in water has a density of 1.11 g/mL.What is the molality?

Fresh air contains approximately 400 ppm CO2,whereas the breath of an intoxicated person contains about 4 percent CO2.The amount of CO2 in the breath of an intoxicated person is ________ times the amount of CO2 in fresh air.

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 = 0.520.

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

A solution is prepared by dissolving 50.0 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?

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

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 290.mm Hg?

What is the molality of ethanol in a solution made by dissolving 7.30 g of ethanol,C₂H₅OH,in 53.6 g of water?

What is the expected freezing point of a 0.50 m solution of K₂SO₄ in water? K_f for water is 1.86°C/m.

A 1.40 M solution of CaCl₂ in water has a density of 1.11 g/mL.What is the molality?

Fresh air contains approximately 400 ppm CO₂,whereas the breath of an intoxicated person contains about 4 percent CO₂.The amount of CO₂ in the breath of an intoxicated person is ________ times the amount of CO₂ in fresh air.