Question 1

How many moles of bromide ions are present in 750.0 mL of 1.35 M MgBr₂?

Accepted Answer

The answer of How many moles of bromide ions are...

Question 2

Diethyl ether has a vapor pressure of 400.0 torr at 18°C. When a sample of benzoic acid is dissolved in ether, the vapor pressure of the solution is 342 torr. What is the mole fraction of benzoic acid in the solution?

Accepted Answer

We can use Raoult's law to solve for the mole fraction of benzoic acid:

P_total = X_ether * P_ether + X_benzoicacid * P_benzoicacid

where P_total is the total vapor pressure of the solution, P_ether is the vapor pressure of diethyl ether, and P_benzoicacid is the vapor pressure of benzoic acid (which we assume to be negligible compared to P_ether). X_ether and X_benzoicacid are the mole fractions of diethyl ether and benzoic acid, respectively.

We can rearrange this equation to solve for X_benzoicacid:

X_benzoicacid = (P_total - X_ether * P_ether) / P_benzoicacid

Plugging in the given values:

X_benzoicacid = (342 torr - 0.60 * 400.0 torr) / 0.0 torr = 0.145

Therefore, the mole fraction of benzoic acid in the solution is 0.145.

Question 3

How many moles of sulfate ions are present in 1.0 L of 0.5 M Li₂SO₄?

Accepted Answer

In a 0.5 M solution of Li₂SO₄, there are 0.5 moles of Li₂SO₄ per liter. Each formula unit of Li₂SO₄ contains one sulfate ion (SO₄²⁻), so there are 0.5 moles of sulfate ions in 1.0 L of the solution.

Question 4

How many moles of solute particles are present in 100.0 mL of 2.50 M (NH₄)₃PO₄?

Accepted Answer

The answer of How many moles of solute particles are...

Question 5

Which of the following aqueous liquids will have the lowest freezing point?

Accepted Answer

The freezing point depression depends on the number of particles in solution. Li₃PO₄ dissociates into 4 ions (3 Li⁺ and 1 PO₄^3-), which is the highest among the given options, leading to the lowest freezing point.

Question 6

Calculate the vapor pressure of a solution prepared by dissolving 0.500 mol of a non-volatile solute in 275 g of hexane (ℳ = 86.18 g/mol) at 49.6°C. P°_hexane = 400.0 torr at 49.6°C.

Accepted Answer

The vapor pressure of the solution can be calculated using Raoult's Law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent. First, calculate the moles of hexane (solvent):$$ \text{Moles of hexane} = \frac{\text{Mass of hexane}}{\text{Molar mass of hexane}} = \frac{275 \, \text{g}}{86.18 \, \text{g/mol}} = 3.19 \, \text{mol} $$Next, calculate the mole fraction of hexane:$$ \text{Mole fraction of hexane} = \frac{\text{Moles of hexane}}{\text{Moles of hexane} + \text{Moles of solute}} = \frac{3.19}{3.19 + 0.500} = \frac{3.19}{3.69} = 0.865 $$Finally, apply Raoult's Law to find the vapor pressure of the solution:$$ \text{Vapor pressure of solution} = \text{Mole fraction of hexane} \times \text{Vapor pressure of pure hexane} = 0.865 \times 400.0 \, \text{torr} = 346 \, \text{torr} $$

Question 7

Two aqueous solutions are prepared: 2.0 m Cu(NO₃)₂and 2.0 m NaBr. Which of the following statements is true?

Accepted Answer

The Cu(NO3)2 solution will dissociate into three ions (one Cu2+ and two NO3-) per formula unit, while NaBr will dissociate into two ions (one Na+ and one Br-) per formula unit. Solutions with a higher concentration of ions (or particles) have lower vapor pressure and lower freezing points due to colligative properties. Therefore, the Cu(NO3)2 solution, having more ions, will have a lower vapor pressure and a lower freezing point than the NaBr solution.

Question 8

From the following list of aqueous solutions and water, select the one with the lowest freezing point.

Accepted Answer

The freezing point depression is determined by the van't Hoff factor (i) and molality (m). (NH4)3PO4 dissociates into 4 ions, giving it the highest van't Hoff factor among the options, resulting in the greatest freezing point depression.

Question 9

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of the non-volatile solute in the solution?

Accepted Answer

The mole fraction of the non-volatile solute in the solution can be calculated using Raoult's law, which states that the vapor pressure of a solvent above a solution (P_solution) is equal to the vapor pressure of the pure solvent (P_pure) multiplied by the mole fraction of the solvent (X_solvent). The decrease in vapor pressure is due to the presence of the non-volatile solute, so we can find the mole fraction of the solute by understanding the change in vapor pressure.Given:- Vapor pressure of pure acetone (P_pure) = 266 torr- Vapor pressure of acetone with non-volatile solute (P_solution) = 232 torrFirst, calculate the mole fraction of acetone (solvent) in the solution:$$X_{solvent} = \frac{P_{solution}}{P_{pure}} = \frac{232}{266} \approx 0.87$$Since the mole fraction of the solvent plus the mole fraction of the solute must equal 1 (because they make up the whole solution), we can find the mole fraction of the solute by subtracting the mole fraction of the solvent from 1:$$X_{solute} = 1 - X_{solvent} = 1 - 0.87 = 0.13$$Therefore, the mole fraction of the non-volatile solute in the solution is 0.13.

Question 10

Select the strongest electrolyte from the following set.

Accepted Answer

LiNO3 is a strong electrolyte because it completely dissociates into ions (Li+ and NO3-) in solution, allowing it to conduct electricity very efficiently.

Question 11

Select the weakest electrolyte from the following set.

Accepted Answer

CH3COOH (propionic acid) is a weak electrolyte due to its partial ionization in water. The other compounds listed are all strong electrolytes, fully dissociating into ions in water.

Question 12

Which of the following aqueous solutions will have the lowest osmotic pressure?

Accepted Answer

Osmotic pressure depends on the total concentration of solute particles in solution. KOH, RbCl, and K2SO4 dissociate into ions in solution, increasing the number of particles. CaSO4 and BaCl2 also dissociate, but the concentration of CaSO4 (0.05 m) is lower than the others, resulting in fewer particles and thus the lowest osmotic pressure.

Question 13

Which of the following aqueous solutions should demonstrate the most non-ideal behavior?

Accepted Answer

The solution with the highest concentration of ionic species (Cu2+ and Cl-) is likely to show the most non-ideal behavior due to increased electrostatic interactions between the ions, which can lead to deviations from ideal thermodynamic behavior.

Question 14

Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol (ℳ = 46.07 g/mol). P°_ethanol = 50.0 torr at 25°C.

Accepted Answer

The answer of Safrole is used as a topical antiseptic....

Question 15

Determine the freezing point of a solution that contains 0.31 mol of sucrose in 175 g of water. K_f = 1.86°C/m

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 sucrose, a non-electrolyte), Kf is the freezing point depression constant (1.86°C/m), and m is the molality of the solution. Molality (m) = moles of solute / kg of solvent = 0.31 mol / 0.175 kg = 1.7714 m. ΔTf = 1 * 1.86°C/m * 1.7714 m = 3.3°C. The freezing point of pure water is 0°C, so the freezing point of the solution is 0°C - 3.3°C = -3.3°C.

Question 16

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution?

Accepted Answer

The mole fraction of acetone in the solution can be calculated using Raoult's law, which states that the vapor pressure of a solvent in a solution is equal to the vapor pressure of the pure solvent multiplied by the mole fraction of the solvent in the solution. Thus, $ \frac{232 \, \text{torr}}{266 \, \text{torr}} = 0.87 $, indicating the mole fraction of acetone is 0.87.

Question 17

What concentration of aqueous FeCl₃ would have the same osmotic pressure as a 0.20 M solution of CaCl₂ at the same temperature, assuming ideal behavior?

Accepted Answer

The osmotic pressure depends on the number of particles in solution. CaCl2 dissociates into 3 ions (1 Ca2+ and 2 Cl-), so a 0.20 M solution has an effective concentration of 0.60 M in terms of particles. FeCl3 dissociates into 4 ions (1 Fe3+ and 3 Cl-), so to have the same osmotic pressure, the concentration of FeCl3 should be 0.15 M (0.15 M x 4 = 0.60 M).

Question 18

Which of the following aqueous solutions should demonstrate the most ideal behavior?

Accepted Answer

NaCl is a simple ionic compound that dissociates completely upon dissolution, yielding Na+ and Cl- ions. This makes it an ideal electrolyte and allows it to demonstrate the most ideal behavior.

Question 19

From the following list of aqueous solutions and water, select the one with the highest boiling point.

Accepted Answer

The boiling point elevation depends on the number of particles in solution. CuCl₂ dissociates into three ions (Cu²⁺ and 2 Cl^-), providing the highest number of particles per mole among the given options, leading to the highest boiling point elevation.

Question 20

Two aqueous are prepared: 1.00 m Na₂CO₃ and 1.00 m LiCl. Which of the following statements is true?

Accepted Answer

The Na2CO3 solution will dissociate into three ions (2 Na+ and 1 CO3^2-), while LiCl will dissociate into two ions (Li+ and Cl-). This means the Na2CO3 solution will have a higher osmotic pressure due to more particles in solution. Solutions with higher osmotic pressure typically have higher boiling points due to the colligative property of boiling point elevation.

Quiz 13: The Properties of Mixtures: Solutions and Colloids

How many moles of bromide ions are present in 750.0 mL of 1.35 M MgBr₂?

Diethyl ether has a vapor pressure of 400.0 torr at 18°C. When a sample of benzoic acid is dissolved in ether, the vapor pressure of the solution is 342 torr. What is the mole fraction of benzoic acid in the solution?

How many moles of sulfate ions are present in 1.0 L of 0.5 M Li₂SO₄?

How many moles of solute particles are present in 100.0 mL of 2.50 M (NH₄) ₃PO₄?

Which of the following aqueous liquids will have the lowest freezing point?

Calculate the vapor pressure of a solution prepared by dissolving 0.500 mol of a non-volatile solute in 275 g of hexane (ℳ = 86.18 g/mol) at 49.6°C. P°_hexane = 400.0 torr at 49.6°C.

Two aqueous solutions are prepared: 2.0 m Cu(NO₃) ₂and 2.0 m NaBr. Which of the following statements is true?

From the following list of aqueous solutions and water, select the one with the lowest freezing point.

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of the non-volatile solute in the solution?

Select the strongest electrolyte from the following set.

Select the weakest electrolyte from the following set.

Which of the following aqueous solutions will have the lowest osmotic pressure?

Which of the following aqueous solutions should demonstrate the most non-ideal behavior?

Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol (ℳ = 46.07 g/mol) . P°_ethanol = 50.0 torr at 25°C.

Determine the freezing point of a solution that contains 0.31 mol of sucrose in 175 g of water. K_f = 1.86°C/m

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution?

What concentration of aqueous FeCl₃ would have the same osmotic pressure as a 0.20 M solution of CaCl₂ at the same temperature, assuming ideal behavior?

Which of the following aqueous solutions should demonstrate the most ideal behavior?

From the following list of aqueous solutions and water, select the one with the highest boiling point.

Two aqueous are prepared: 1.00 m Na₂CO₃ and 1.00 m LiCl. Which of the following statements is true?

Quiz 13: The Properties of Mixtures: Solutions and Colloids

How many moles of bromide ions are present in 750.0 mL of 1.35 M MgBr2?

Diethyl ether has a vapor pressure of 400.0 torr at 18°C. When a sample of benzoic acid is dissolved in ether, the vapor pressure of the solution is 342 torr. What is the mole fraction of benzoic acid in the solution?

How many moles of sulfate ions are present in 1.0 L of 0.5 M Li2SO4?

How many moles of solute particles are present in 100.0 mL of 2.50 M (NH4) 3PO4?

Which of the following aqueous liquids will have the lowest freezing point?

Calculate the vapor pressure of a solution prepared by dissolving 0.500 mol of a non-volatile solute in 275 g of hexane (ℳ = 86.18 g/mol) at 49.6°C. P°hexane = 400.0 torr at 49.6°C.

Two aqueous solutions are prepared: 2.0 m Cu(NO3) 2 and 2.0 m NaBr. Which of the following statements is true?

From the following list of aqueous solutions and water, select the one with the lowest freezing point.

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of the non-volatile solute in the solution?

Select the strongest electrolyte from the following set.

Select the weakest electrolyte from the following set.

Which of the following aqueous solutions will have the lowest osmotic pressure?

Which of the following aqueous solutions should demonstrate the most non-ideal behavior?

Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol (ℳ = 46.07 g/mol) . P°ethanol = 50.0 torr at 25°C.

Determine the freezing point of a solution that contains 0.31 mol of sucrose in 175 g of water. Kf = 1.86°C/m

The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution?

What concentration of aqueous FeCl3 would have the same osmotic pressure as a 0.20 M solution of CaCl2 at the same temperature, assuming ideal behavior?

Which of the following aqueous solutions should demonstrate the most ideal behavior?

From the following list of aqueous solutions and water, select the one with the highest boiling point.

Two aqueous are prepared: 1.00 m Na2CO3 and 1.00 m LiCl. Which of the following statements is true?

How many moles of bromide ions are present in 750.0 mL of 1.35 M MgBr₂?

How many moles of sulfate ions are present in 1.0 L of 0.5 M Li₂SO₄?

How many moles of solute particles are present in 100.0 mL of 2.50 M (NH₄) ₃PO₄?

Calculate the vapor pressure of a solution prepared by dissolving 0.500 mol of a non-volatile solute in 275 g of hexane (ℳ = 86.18 g/mol) at 49.6°C. P°_hexane = 400.0 torr at 49.6°C.

Two aqueous solutions are prepared: 2.0 m Cu(NO₃) ₂and 2.0 m NaBr. Which of the following statements is true?

Safrole is used as a topical antiseptic. Calculate the vapor pressure of a solution prepared by dissolving 0.75 mol of safrole in 950 g of ethanol (ℳ = 46.07 g/mol) . P°_ethanol = 50.0 torr at 25°C.

Determine the freezing point of a solution that contains 0.31 mol of sucrose in 175 g of water. K_f = 1.86°C/m

What concentration of aqueous FeCl₃ would have the same osmotic pressure as a 0.20 M solution of CaCl₂ at the same temperature, assuming ideal behavior?

Two aqueous are prepared: 1.00 m Na₂CO₃ and 1.00 m LiCl. Which of the following statements is true?