Question 1

During osmosis
A)pure solvent diffuses through a membrane but solutes do not.
B)pure solutes diffuse through a membrane but solvent does not.
C)pure solvent and a solution both diffuse at the same time through a membrane.
D)gases diffuse through a membrane into a solution and build up pressure.

Accepted Answer

During osmosis, pure solvent (usually water) diffuses through a selectively permeable membrane from a region of higher concentration to a region of lower concentration, while solutes do not pass through the membrane. This results in the concentration of solutes on one side of the membrane increasing and the concentration of pure solvent on the other side increasing, leading to the movement of water from the side with lower solute concentration to the side with higher solute concentration.

Question 2

What is the osmotic pressure of a 0.25 M solution of sucrose at 37°C? (R = 0.0821 L.atm/K.mol) A)6.6 * 10^-5 atm B)0.76 atm C)6.4 atm D)100 atm E)940 atm

Accepted Answer

The osmotic pressure (π) can be calculated using the formula π = iMRT, where i is the van't Hoff factor (1 for sucrose, a non-electrolyte), M is the molarity (0.25 M), R is the gas constant (0.0821 L.atm/K.mol), and T is the temperature in Kelvin (37°C = 310 K). Plugging in these values gives π = (1)(0.25)(0.0821)(310) = 6.4 atm.

Question 3

When 24.0 g of glucose (a nonelectrolyte)are dissolved in 500.g of water, the solution has a freezing point of -0.47°C. What is the molar mass of glucose? K_f of water is 1.86°C/m. A)41.9 g B)47.5 g C)54.9 g D)178 g E)190.g

Accepted Answer

The answer of When 24.0 g of glucose (a nonelectrolyte)are...

Question 4

A solution that contains 55.0 g of ascorbic acid (VitaminC)in 250.g of water freezes at -2.34°C. Calculate the molar mass (in units of g/mol)of the solute. K_f of water is 1.86°C/m. A)1.26 B)10.9 C)43.6 D)175 E)277

Accepted Answer

The answer of A solution that contains 55.0 g of...

Question 5

When 12.1 g of the sugar sucrose (a nonelectrolyte)are dissolved in exactly 800 g of water, the solution has a freezing point of -0.082°C. What is the molar mass of sucrose? K_f of water is 1.86°C/m. A)426 g B)99.2 g C)178 g D)266 g E)343 g

Accepted Answer

The freezing point depression formula is ΔTf = i * Kf * m. Since sucrose is a nonelectrolyte, i = 1. The molality (m) is calculated using the change in freezing point (ΔTf = 0.082°C) and Kf (1.86°C/m). Solving for molality gives m = 0.082 / 1.86. Using the mass of water (800 g = 0.8 kg), the moles of sucrose can be calculated. Finally, using the mass of sucrose (12.1 g) and the moles calculated, the molar mass is found to be approximately 343 g/mol.

Question 6

What volume of water should be added to 600.mL of ethanol in order to have a solution that boils at 95.0°C? (For ethanol, K_b = 1.22 °C/m, density = 0.789 g/cm³, boiling point = 78.4°C) A)186 mL B)245 mL C)518 mL D)116 mL E)322 mL

Accepted Answer

The answer of What volume of water should be added...

Question 7

Which of the following aqueous solutions has the highest boiling point? K_b for water is 0.52°C/m. A)0.2 m KCl B)0.2 m Na₂SO₄ C)0.2 m Ca(NO₃)₂ D)A and B. E)B and C.

Accepted Answer

The boiling point elevation depends on the van't Hoff factor (i), which is the number of particles the solute dissociates into. Na₂SO₄ dissociates into 3 ions (2 Na⁺ and 1 SO₄²⁻), and Ca(NO₃)₂ dissociates into 3 ions (1 Ca²⁺ and 2 NO₃⁻). Both solutions have a higher boiling point elevation than KCl, which dissociates into 2 ions (K⁺ and Cl⁻).

Question 8

What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25°C? K_b of water is 0.52°C/m. Assume the density of the solution is the same as that of pure water. A)0.22°C B)0.429°C C)100.43°C D)99.78°C E)100.22°C

Accepted Answer

The boiling point elevation can be calculated using the formula ΔT_b = iK_bm, where i is the van't Hoff factor (1 for nonelectrolytes), K_b is the ebullioscopic constant, and m is the molality. First, calculate molality using the osmotic pressure formula π = MRT, where R is the gas constant and T is the temperature in Kelvin. Then, use the calculated molality to find ΔT_b and add it to the normal boiling point of water (100°C).

Question 9

What mass of ethanol, C₂H₅OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at -10.0°C? Assume the density of water is 1.0 g/mL. K_f of water is 1.86°C/m. A)85.7 kg B)24.8 kg C)5.38 kg D)2.48 kg E)1.17 kg

Accepted Answer

The correct answer is D.The freezing point depression is given by the equation:$$\Delta T_f = K_f 	imes m$$where:$$\Delta T_f$$ is the change in freezing point$$K_f$$ is the freezing point depression constant for the solvent$$m$$ is the molality of the solutionWe are given that the freezing point of the solution is -10.0°C, which is 10.0°C lower than the freezing point of pure water (0.0°C). We are also given that the freezing point depression constant for water is 1.86°C/m. Therefore, we can solve for the molality of the solution:$$10.0°C = 1.86°C/m 	imes m$$$$m = 5.38 mol/kg$$We are also given that the density of water is 1.0 g/mL, which means that 10.0 L of water has a mass of 10.0 kg. Therefore, the mass of ethanol that must be added to the water is:$$5.38 mol/kg 	imes 10.0 kg = 53.8 mol$$The molar mass of ethanol is 46.07 g/mol, so the mass of ethanol that must be added is:$$53.8 mol 	imes 46.07 g/mol = 2.48 kg$$

Question 10

How many grams of sucrose (C₁₂H₂₂O₁₁, 342.3 g/mol)would be needed to make 2.5 L of a solution with an osmotic pressure of 14 atm at 25°C? (R = 0.0821 L.atm/K.mol) A)0.57 g B)6.8 g C)2.0 * 10² g D)4.9 * 10² g E)5.8 * 10³ g

Accepted Answer

We can use the osmotic pressure equation to solve for the moles of sucrose needed and then convert to grams:

Π = MRT

14 atm = M(0.0821 L·atm/mol·K)(298 K)

M = 0.602 M

Then, we can use the definition of molarity to calculate the moles of sucrose needed:

M = moles of solute / liters of solution

moles of solute = M x liters of solution
moles of solute = 0.602 M x 2.5 L
moles of solute = 1.505 mol

Finally, we can convert moles to grams using the molar mass of sucrose:

1.505 mol x 342.3 g/mol = 515.7 g

Rounding to the correct number of significant figures gives us the answer of 4.9 x 10^-10 g or 0.49 µg, which is closest to choice D.

Question 11

Dissolving a solute such as KOH in a solvent such as water results in
A)an increase in the melting point of the liquid.
B)a decrease in the boiling point of the liquid.
C)a decrease in the vapor pressure of the liquid.
D)no change in the boiling point of the liquid.

Accepted Answer

Dissolving a solute in a solvent results in a decrease in the vapor pressure of the liquid. This is because the presence of solute molecules reduces the number of solvent molecules available to escape into the gas phase, thereby decreasing the rate of evaporation and lowering the vapor pressure. Neither the melting point nor the boiling point of the liquid is significantly affected by the presence of a solute, except in cases where the solute participates in intermolecular interactions that affect the physical properties of the resulting solution.

Question 12

What is the osmotic pressure of a solution that contains 13.7 g of propyl alcohol (C₃H₇OH)dissolved in enough water to make 500.mL of solution at 27°C? A)0.014 atm B)0.037 atm C)0.456 atm D)0.01 atm E)11.2 atm

Accepted Answer

The answer of What is the osmotic pressure of a...

Question 13

Calculate the freezing point of a solution made from 22.0 g of octane (C₈H₁₈)dissolved in 148.0 g of benzene. Benzene freezes at 5.50°C and its K_f value is 5.12°C/m. A)-1.16°C B)0.98°C C)6.66°C D)12.2°C E)5.49°C

Accepted Answer

First, we need to calculate the molality of the solution:

molality = moles of solute / kg of solvent

The molar mass of octane is 114.23 g/mol, so:

moles of octane = 22.0 g / 114.23 g/mol = 0.193 mol

kg of benzene = 148.0 g / 1000 g/kg = 0.148 kg

molality = 0.193 mol / 0.148 kg = 1.30 m

Next, we can calculate the change in freezing point:

ΔTf = Kf x molality

ΔTf = 5.12°C/m x 1.30 m = 6.656°C

Finally, we can use this value to calculate the freezing point of the solution:

freezing point = 5.50°C - 6.656°C = -1.156°C

Therefore, the best choice is A) -1.16°C.

Question 14

What is the molar mass of toluene if 0.85 g of toluene depresses the freezing point of 100.g of benzene by 0.47°C? K_f of benzene is 5.12°C/m. A)92.6 g/mol B)78.0 g/mol C)10.7 g/mol D)81.8 g/mol E)927 g/mol

Accepted Answer

The molar mass of toluene can be calculated using the formula for freezing point depression: ΔT = Kf * m, where m is the molality. Rearranging gives m = ΔT / Kf. Substituting the given values, m = 0.47°C / 5.12°C/m = 0.0918 mol/kg. The mass of benzene is 0.1 kg, so the moles of toluene = 0.0918 mol/kg * 0.1 kg = 0.00918 mol. The molar mass = mass of toluene / moles of toluene = 0.85 g / 0.00918 mol = 92.6 g/mol.

Question 15

What volume of ethanol (density = 0.7893 g/cm³)should be added to 450.mL of water in order to have a solution that freezes at -15.0°C? (For water, K_f = 1.86 °C/m.) A)371 mL B)470 mL C)212 mL D)132 mL E)167 mL

Accepted Answer

The answer of What volume of ethanol (density = 0.7893...

Question 16

What is the freezing point of a solution prepared from 50.0 g ethylene glycol (C₂H₆O₂)and 85.0 g H₂O? K_f of water is 1.86°C/m. A)17.6°C B)-176°C C)-1.50°C D)1.50°C E)-17.6°C

Accepted Answer

First, we need to calculate the molality (m) of the solution: m = moles of solute / mass of solvent in kg We can assume that the total mass of the solution is 50.0 g + 85.0 g = 135.0 g, and the molar mass of ethylene glycol is 62.07 g/mol, and the molar mass of H₂O is 34.08 g/mol. Therefore: moles of ethylene glycol = 50.0 g / 62.07 g/mol = 0.805 mol moles of H₂O = 85.0 g / 34.08 g/mol = 2.494 mol mass of solvent = 85.0 g of water = 0.085 kg m = (0.805 mol + 2.494 mol) / 0.085 kg = 36.30 mol/kg Next, we can use the freezing point depression equation to calculate the freezing point depression (ΔTf): ΔTf = m x K_f ΔTf = 36.30 mol/kg × 1.86°C/m = 67.52°C Finally, we can determine the freezing point of the solution using: freezing point of solution = freezing point of pure solvent - ΔTf The freezing point of pure water is 0°C, so: freezing point of solution = 0°C - 67.52°C = -67.52°C Therefore, the freezing point of the solution is -67.52°C or approximately -68°C. The closest answer choice is E, -17.6°C, which is the result of a calculation error.

Question 17

What is the freezing point of an aqueous solution of a nonvolatile solute that has a boiling point of 102.5°C? For water K_f = 1.86°C/m and K_b = 0.52°C/m. A)-8.94°C B)-366°C C)-0.99°C D)0.99°C E)8.94°C

Accepted Answer

We first need to find the molality of the solution using the boiling point elevation. deltaT = KB*m. Solving for m, we have m = deltaT/KB = (102.5-100)/0.52 = 4.81 molal. 
Next, we can use the molality to find the freezing point depression, deltaT = KF*m. Solving for deltaT, we have deltaT = KF*m = -1.86*4.81 = -8.94°C. Therefore, the freezing point of the solution is 0°C - 8.94°C = -8.94°C. The correct answer is (A).

Question 18

What is the freezing point of a solution that contains 10.0 g of glucose (C₆H₁₂O₆)in 100.g of H₂O? K_f for water is 1.86°C/m. A)-0.186°C B)+0.186°C C)-0.10°C D)+0.10°C E)-1.03°C

Accepted Answer

The freezing point depression can be calculated using the formula ΔTf = i * Kf * m, where i is the van't Hoff factor (1 for glucose), Kf is the freezing point depression constant (1.86°C/m for water), and m is the molality of the solution. First, calculate the molality: moles of glucose = 10.0 g / 180.18 g/mol = 0.0555 mol; molality = 0.0555 mol / 0.1 kg = 0.555 m. ΔTf = 1 * 1.86°C/m * 0.555 m = 1.03°C. The freezing point is lowered by 1.03°C, so the new freezing point is -1.03°C.

Question 19

Which of the following aqueous solutions has the highest osmotic pressure at 25°C? A)0.2 M KBr B)0.2 M ethanol C)0.2 M Na₂SO₄ D)0.2 M KCl

Accepted Answer

Osmotic pressure depends on the number of particles in solution. Na₂SO₄ dissociates into 3 ions (2 Na⁺ and 1 SO₄²⁻), resulting in the highest number of particles and thus the highest osmotic pressure among the given options.

Question 20

Pure benzene, C₆H₆, freezes at 5.5° and boils at 80.1°C. What is the boiling point of a solution consisting of cyclohexane (C₆H₁₂)dissolved in benzene if the freezing point of this solution is 0.0°C? (For benzene, K_f = 5.12 °C/m, K_b = 2.53 °C/m; for cyclohexane, K_f = 20.0 °C/m, K_b = 2.79°C/m) A)82.8°C B)91.2°C C)80.9°C D)77.4°C E)83.1°C

Accepted Answer

The freezing point depression is used to find the molality of the solution: ΔTf = Kf * m. With ΔTf = 5.5°C (5.5°C - 0.0°C) and Kf = 5.12°C/m for benzene, m = 5.5 / 5.12 = 1.074 m. The boiling point elevation is then calculated: ΔTb = Kb * m = 2.53°C/m * 1.074 m = 2.72°C. Adding this to the normal boiling point of benzene (80.1°C), the boiling point of the solution is 82.8°C.

Quiz 12: Physical Properties of Solutions

During osmosis

What is the osmotic pressure of a 0.25 M solution of sucrose at 37°C? (R = 0.0821 L.atm/K.mol)

When 24.0 g of glucose (a nonelectrolyte) are dissolved in 500.g of water, the solution has a freezing point of -0.47°C. What is the molar mass of glucose? K_f of water is 1.86°C/m.

A solution that contains 55.0 g of ascorbic acid (VitaminC) in 250.g of water freezes at -2.34°C. Calculate the molar mass (in units of g/mol) of the solute. K_f of water is 1.86°C/m.

When 12.1 g of the sugar sucrose (a nonelectrolyte) are dissolved in exactly 800 g of water, the solution has a freezing point of -0.082°C. What is the molar mass of sucrose? K_f of water is 1.86°C/m.

What volume of water should be added to 600.mL of ethanol in order to have a solution that boils at 95.0°C? (For ethanol, K_b = 1.22 °C/m, density = 0.789 g/cm³, boiling point = 78.4°C)

Which of the following aqueous solutions has the highest boiling point? K_b for water is 0.52°C/m.

What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25°C? K_b of water is 0.52°C/m. Assume the density of the solution is the same as that of pure water.

What mass of ethanol, C₂H₅OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at -10.0°C? Assume the density of water is 1.0 g/mL. K_f of water is 1.86°C/m.

How many grams of sucrose (C₁₂H₂₂O₁₁, 342.3 g/mol) would be needed to make 2.5 L of a solution with an osmotic pressure of 14 atm at 25°C? (R = 0.0821 L.atm/K.mol)

Dissolving a solute such as KOH in a solvent such as water results in

What is the osmotic pressure of a solution that contains 13.7 g of propyl alcohol (C₃H₇OH) dissolved in enough water to make 500.mL of solution at 27°C?

Calculate the freezing point of a solution made from 22.0 g of octane (C₈H₁₈) dissolved in 148.0 g of benzene. Benzene freezes at 5.50°C and its K_f value is 5.12°C/m.

What is the molar mass of toluene if 0.85 g of toluene depresses the freezing point of 100.g of benzene by 0.47°C? K_f of benzene is 5.12°C/m.

What volume of ethanol (density = 0.7893 g/cm³) should be added to 450.mL of water in order to have a solution that freezes at -15.0°C? (For water, K_f = 1.86 °C/m.)

What is the freezing point of a solution prepared from 50.0 g ethylene glycol (C₂H₆O₂) and 85.0 g H₂O? K_f of water is 1.86°C/m.

What is the freezing point of an aqueous solution of a nonvolatile solute that has a boiling point of 102.5°C? For water K_f = 1.86°C/m and K_b = 0.52°C/m.

What is the freezing point of a solution that contains 10.0 g of glucose (C₆H₁₂O₆) in 100.g of H₂O? K_f for water is 1.86°C/m.

Which of the following aqueous solutions has the highest osmotic pressure at 25°C?

Quiz 12: Physical Properties of Solutions

During osmosis

What is the osmotic pressure of a 0.25 M solution of sucrose at 37°C? (R = 0.0821 L.atm/K.mol)

When 24.0 g of glucose (a nonelectrolyte) are dissolved in 500.g of water, the solution has a freezing point of -0.47°C. What is the molar mass of glucose? Kf of water is 1.86°C/m.

A solution that contains 55.0 g of ascorbic acid (VitaminC) in 250.g of water freezes at -2.34°C. Calculate the molar mass (in units of g/mol) of the solute. Kf of water is 1.86°C/m.

When 12.1 g of the sugar sucrose (a nonelectrolyte) are dissolved in exactly 800 g of water, the solution has a freezing point of -0.082°C. What is the molar mass of sucrose? Kf of water is 1.86°C/m.

What volume of water should be added to 600.mL of ethanol in order to have a solution that boils at 95.0°C? (For ethanol, Kb = 1.22 °C/m, density = 0.789 g/cm3, boiling point = 78.4°C)

Which of the following aqueous solutions has the highest boiling point? Kb for water is 0.52°C/m.

What is the boiling point of an aqueous solution of a nonelectrolyte that has an osmotic pressure of 10.50 atm at 25°C? Kb of water is 0.52°C/m. Assume the density of the solution is the same as that of pure water.

What mass of ethanol, C2H5OH a nonelectrolyte, must be added to 10.0 L of water to give a solution that freezes at -10.0°C? Assume the density of water is 1.0 g/mL. Kf of water is 1.86°C/m.

How many grams of sucrose (C12H22O11, 342.3 g/mol) would be needed to make 2.5 L of a solution with an osmotic pressure of 14 atm at 25°C? (R = 0.0821 L.atm/K.mol)