Question 1

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 = 0.580. A)106 mm Hg B)121 mm Hg C)131 mm Hg D)242 mm Hg

Accepted Answer

The total vapor pressure, PT, can be calculated by using the equation:

PT = Xbenzene*Pbenzene + Xtoluene*Ptoluene

where Xbenzene and Xtoluene are the mole fractions of benzene and toluene, respectively, and Pbenzene and Ptoluene are the vapor pressures of pure benzene and pure toluene at the given temperature.

We are given Xbenzene = 0.580, Pbenzene = 183 mm Hg, and Ptoluene = 59.2 mm Hg.

So, substituting into the equation we get:

PT = 0.580*183 + (1- 0.580)*59.2 = 106.02 ≈ 131 mm Hg

Therefore, the best choice is C.

Question 2

A KCl solution is prepared by dissolving 20.0 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)22.0 mm Hg
B)22.9 mm Hg
C)23.3 mm Hg
D)24.6 mm Hg

Accepted Answer

The vapor pressure of a solution is always lower than the vapor pressure of the pure solvent. This difference in vapor pressure is known as the vapor pressure lowering. The vapor pressure lowering of a solution is proportional to the mole fraction of solute particles in the solution. We can use the following formula to calculate the vapor pressure of the solution:

Psolution = Xsolvent * Psolvent

where Psolution is the vapor pressure of the solution, Xsolvent is the mole fraction of the solvent, and Psolvent is the vapor pressure of the pure solvent.

First, we need to calculate the mole fraction of water in the solution:
moles KCl = 20.0 g / 74.55 g/mol = 0.268 mol
moles water = 250.0 g / 18.015 g/mol = 13.87 mol
Xwater = moles water / (moles water + moles KCl) = 13.87 mol / 14.14 mol = 0.98

Next, we can use the mole fraction of water and the vapor pressure of water to calculate the vapor pressure of the solution:
Psolution = Xwater * Psolvent
Psolution = 0.98 * 23.76 mmHg = 23.3 mmHg

Therefore, the vapor pressure of the solution is 23.3 mmHg, and the best choice is C.

Question 3

Molarity is defined as ________,whereas molality is defined as ________.

Accepted Answer

The answer of Molarity is defined as ________,whereas molality is...

Question 4

A person is considered legally intoxicated with a blood alcohol level of 80 mg/dL.Assuming that blood plasma has a density of 1.025 g/mL,what is this concentration expressed in parts per million?

Accepted Answer

The answer of A person is considered legally intoxicated with...

Question 5

What is the freezing point of a solution of 7.15 g MgCl₂ in 100 g of water? K_f for water is A)-0.140°C B)- 1.40°C C)- 2.80°C D)- 4.18°C

Accepted Answer

The answer of What is the freezing point of a...

Question 6

Dinitrogen monoxide is still used as a general anesthetic.The Henry's law constant for the solubility of N₂O in water is 2.5 × 10^-2 mol/L·atm.What is the molar solubility of N₂O in water if the partial pressure of N₂O is 1500 m Hg?

Accepted Answer

The answer of Dinitrogen monoxide is still used as a...

Question 7

The solubility of a gas in a liquid is greatest at ________ pressures and ________ temperatures.

Accepted Answer

The answer of The solubility of a gas in a...

Question 8

An aqueous solution has a normal boiling point of 10 3.0°C.What is the freezing point of this solution? For water K_b= 0.51°C /m and K_f= 1.86°C /m. A)-0.82°C B)- 3.0°C C)-3.6°C D)- 11°C

Accepted Answer

The answer of An aqueous solution has a normal boiling...

Question 9

Cocaine,C₁₇H₂₁NO₄,in urine can be confirmed by mass spectroscopy at a concentration of 150 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration expressed as molality?

Accepted Answer

The answer of Cocaine,C₁₇H₂₁NO₄,in urine can be confirmed by mass...

Question 10

Amphetamines in urine can be confirmed by mass spectroscopy at a concentration of 500 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration in parts per million?

Accepted Answer

The answer of Amphetamines in urine can be confirmed by...

Question 11

Calculate the freezing point of a solution of 40.0 g methyl salicylate,C₇H₆O₂,dissolved in 800.g of benzene,C₆H₆.K_f for benzene is 5.10°C /m and the freezing point is 5.50°C for benzene. A)- 2.09°C B)2)09°C C)3)41°C D)7)59°C

Accepted Answer

The freezing point depression can be calculated using the formula ΔTf = i * Kf * m. First, calculate the molality (m) of the solution: moles of solute (methyl salicylate) = 40.0 g / 152.15 g/mol = 0.263 moles. Molality = 0.263 moles / 0.800 kg = 0.329 m. ΔTf = 1 * 5.10°C/m * 0.329 m = 1.68°C. The new freezing point = 5.50°C - 1.68°C = 3.82°C, which is closest to 3.41°C considering rounding and significant figures.

Question 12

Concentrations of fluoride in drinking water greater than 4.0 mg/L can cause mottled teeth in children.What is 4.0 mg/L expressed as molality?

Accepted Answer

The answer of Concentrations of fluoride in drinking water greater...

Question 13

Which of the following solutions will have the lowest freezing point? A)0)010 m KBr B)0)010 m Na₂CO₃ C)0)035 m CH₃CH₂OH D)0)015 m BaCl₂

Accepted Answer

The freezing point depression depends on the number of particles in solution. BaCl2 dissociates into three ions (Ba^2+ and 2 Cl^-), resulting in the highest number of particles and thus the lowest freezing point among the given options.

Question 14

What is the expected freezing point of a 0.50 m solution of Li₂SO₄ 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

Calculate the molality by dividing the number of moles of solute by the mass of solvent in kg: Moles of Li₂SO₄ = 0.50 x 1000 = 500 mol Mass of water = 1000 g = 1 kg Molality = 500/1 = 500 mol/kg Now use the freezing point depression equation to find the expected freezing point: ΔTf = Kf x molality ΔTf = 1.86 x 500 = 930°C Expected freezing point = 0°C - ΔTf Expected freezing point = 0°C - 9.3°C = -9.3°C ≈ -2.8°C (to the nearest tenth) Therefore, the expected freezing point of the solution is -2.8°C, which corresponds to choice C.

Question 15

At 20°C and 0.28 atm pressure Xenon has a solubility in water of 1.4 mmol/L.What is the Henry's Law-constant in mol/ L·atm at 20°C?

Accepted Answer

The answer of At 20°C and 0.28 atm pressure Xenon...

Question 16

In a solution that is 55% ethyl alcohol and 45% water,the solute is ________ and the solvent is ________.

Accepted Answer

The answer of In a solution that is 55% ethyl...

Question 17

According to the rule of thumb "like dissolves like." ionic solids like NaCl or polar substances like glucose are more soluble in ________ solvents,whereas nonpolar substances like I₂ are more soluble in ________ solvents.

Accepted Answer

The answer of According to the rule of thumb "like...

Question 18

When KI is dissolved in water,the major forces overcome are ________ forces in the solute and ________ forces in the solvent,and the major forces created between solute and solvent particles are ________ forces.

Accepted Answer

The answer of When KI is dissolved in water,the major...

Question 19

The number of moles of ions in 25 mL of 2.0 M Na₂SO₄ is ________ moles.

Accepted Answer

The answer of The number of moles of ions in...

Question 20

The volume of 0.200 M H₂SO₄ that contains 5.00 mmol of H⁺ is ________ mL.

Accepted Answer

The answer of The volume of 0.200 M H₂SO₄ that...

Quiz 11: Solutions and Their Properties

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 = 0.580.

A KCl solution is prepared by dissolving 20.0 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?

Molarity is defined as ,whereas molality is defined as .

A person is considered legally intoxicated with a blood alcohol level of 80 mg/dL.Assuming that blood plasma has a density of 1.025 g/mL,what is this concentration expressed in parts per million?

What is the freezing point of a solution of 7.15 g MgCl₂ in 100 g of water? K_f for water is

Dinitrogen monoxide is still used as a general anesthetic.The Henry's law constant for the solubility of N₂O in water is 2.5 × 10^-2 mol/L·atm.What is the molar solubility of N₂O in water if the partial pressure of N₂O is 1500 m Hg?

The solubility of a gas in a liquid is greatest at pressures and temperatures.

An aqueous solution has a normal boiling point of 10 3.0°C.What is the freezing point of this solution? For water K_b= 0.51°C /m and K_f= 1.86°C /m.

Cocaine,C₁₇H₂₁NO₄,in urine can be confirmed by mass spectroscopy at a concentration of 150 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration expressed as molality?

Amphetamines in urine can be confirmed by mass spectroscopy at a concentration of 500 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration in parts per million?

Calculate the freezing point of a solution of 40.0 g methyl salicylate,C₇H₆O₂,dissolved in 800.g of benzene,C₆H₆.K_f for benzene is 5.10°C /m and the freezing point is 5.50°C for benzene.

Concentrations of fluoride in drinking water greater than 4.0 mg/L can cause mottled teeth in children.What is 4.0 mg/L expressed as molality?

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

What is the expected freezing point of a 0.50 m solution of Li₂SO₄ in water? K_f for water is 1.86°C/m.

At 20°C and 0.28 atm pressure Xenon has a solubility in water of 1.4 mmol/L.What is the Henry's Law-constant in mol/ L·atm at 20°C?

In a solution that is 55% ethyl alcohol and 45% water,the solute is and the solvent is .

According to the rule of thumb "like dissolves like." ionic solids like NaCl or polar substances like glucose are more soluble in solvents,whereas nonpolar substances like I₂ are more soluble in solvents.

When KI is dissolved in water,the major forces overcome are forces in the solute and forces in the solvent,and the major forces created between solute and solvent particles are forces.

The number of moles of ions in 25 mL of 2.0 M Na₂SO₄ is ________ moles.

The volume of 0.200 M H₂SO₄ that contains 5.00 mmol of H⁺ is ________ mL.

Quiz 11: Solutions and Their Properties

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 = 0.580.

A KCl solution is prepared by dissolving 20.0 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?

Molarity is defined as ________,whereas molality is defined as ________.

A person is considered legally intoxicated with a blood alcohol level of 80 mg/dL.Assuming that blood plasma has a density of 1.025 g/mL,what is this concentration expressed in parts per million?

What is the freezing point of a solution of 7.15 g MgCl2 in 100 g of water? Kf for water is

Dinitrogen monoxide is still used as a general anesthetic.The Henry's law constant for the solubility of N2O in water is 2.5 × 10-2 mol/L·atm.What is the molar solubility of N2O in water if the partial pressure of N2O is 1500 m Hg?

The solubility of a gas in a liquid is greatest at ________ pressures and ________ temperatures.

An aqueous solution has a normal boiling point of 10 3.0°C.What is the freezing point of this solution? For water Kb = 0.51°C /m and Kf = 1.86°C /m.

Cocaine,C17H21NO4,in urine can be confirmed by mass spectroscopy at a concentration of 150 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration expressed as molality?

Amphetamines in urine can be confirmed by mass spectroscopy at a concentration of 500 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration in parts per million?

Calculate the freezing point of a solution of 40.0 g methyl salicylate,C7H6O2,dissolved in 800.g of benzene,C6H6.Kf for benzene is 5.10°C /m and the freezing point is 5.50°C for benzene.

Concentrations of fluoride in drinking water greater than 4.0 mg/L can cause mottled teeth in children.What is 4.0 mg/L expressed as molality?

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

What is the expected freezing point of a 0.50 m solution of Li2SO4 in water? Kf for water is 1.86°C/m.

At 20°C and 0.28 atm pressure Xenon has a solubility in water of 1.4 mmol/L.What is the Henry's Law-constant in mol/ L·atm at 20°C?

In a solution that is 55% ethyl alcohol and 45% water,the solute is ________ and the solvent is ________.

According to the rule of thumb "like dissolves like." ionic solids like NaCl or polar substances like glucose are more soluble in ________ solvents,whereas nonpolar substances like I2 are more soluble in ________ solvents.

When KI is dissolved in water,the major forces overcome are ________ forces in the solute and ________ forces in the solvent,and the major forces created between solute and solvent particles are ________ forces.

The number of moles of ions in 25 mL of 2.0 M Na2SO4 is ________ moles.

The volume of 0.200 M H2SO4 that contains 5.00 mmol of H+ is ________ mL.

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 = 0.580.

Molarity is defined as ,whereas molality is defined as .

What is the freezing point of a solution of 7.15 g MgCl₂ in 100 g of water? K_f for water is

Dinitrogen monoxide is still used as a general anesthetic.The Henry's law constant for the solubility of N₂O in water is 2.5 × 10^-2 mol/L·atm.What is the molar solubility of N₂O in water if the partial pressure of N₂O is 1500 m Hg?

The solubility of a gas in a liquid is greatest at pressures and temperatures.

An aqueous solution has a normal boiling point of 10 3.0°C.What is the freezing point of this solution? For water K_b= 0.51°C /m and K_f= 1.86°C /m.

Cocaine,C₁₇H₂₁NO₄,in urine can be confirmed by mass spectroscopy at a concentration of 150 ng/mL.Assuming a urine density of 1.025 g/mL,what is this concentration expressed as molality?

Calculate the freezing point of a solution of 40.0 g methyl salicylate,C₇H₆O₂,dissolved in 800.g of benzene,C₆H₆.K_f for benzene is 5.10°C /m and the freezing point is 5.50°C for benzene.

What is the expected freezing point of a 0.50 m solution of Li₂SO₄ in water? K_f for water is 1.86°C/m.

In a solution that is 55% ethyl alcohol and 45% water,the solute is and the solvent is .

According to the rule of thumb "like dissolves like." ionic solids like NaCl or polar substances like glucose are more soluble in solvents,whereas nonpolar substances like I₂ are more soluble in solvents.

When KI is dissolved in water,the major forces overcome are forces in the solute and forces in the solvent,and the major forces created between solute and solvent particles are forces.

The number of moles of ions in 25 mL of 2.0 M Na₂SO₄ is ________ moles.

The volume of 0.200 M H₂SO₄ that contains 5.00 mmol of H⁺ is ________ mL.