Quiz 2 - Colligative Properties of Solutions | Colligative Properties of Solutions
General Chemistry 2 - Quiz 2 - Colligative Properties of Solutions
Which factor does not affect the solubility of a solid in a solvent?
The solubility of a solid in a solvent is primarily affected by temperature, the nature of the solute, and the nature of the solvent. Pressure has little to no effect on the solubility of a solid in a liquid, though it significantly affects the solubility of gases in liquids.
Which of the following statements is incorrect?
The solubility of gases typically decreases as temperature increases, making this statement incorrect.
How is the vapor pressure of a solution compared to the vapor pressure of the pure solvent?
The addition of a non-volatile solute to a solvent reduces the solvent's vapor pressure, making the vapor pressure of the solution lower than that of the pure solvent. This occurs because solute particles interfere with the escape of solvent molecules into the vapor phase.
Which of the following concentration units is defined as the number of moles of solute per kilogram of solvent?
Molality is defined as the number of moles of solute per kilogram of solvent, and it is often used in calculations involving colligative properties because it is independent of temperature.
What is the van’t Hoff factor i for Ba(OH)2 (s) dissolved in water?
When Ba(OH)2 dissolves in water, it dissociates into 3 ions: one Ba2+ ion and two OH− ions. The van’t Hoff factor i represents the number of particles into which a compound dissociates in solution, so for Ba(OH)2, i = 3.
What is a semipermeable membrane in the context of osmosis?
In the context of osmosis, a semipermeable membrane allows the passage of solvent molecules (such as water) but blocks the passage of solute particles, creating a concentration gradient and driving the osmotic process.
For a given solution, which colligative property is most directly affected by the van 't Hoff factor?
The van 't Hoff factor (i) represents the number of particles into which a solute dissociates in solution, and it affects all colligative properties, including freezing-point depression, boiling-point elevation, and vapor-pressure lowering.
Which of the following solutions would have the highest boiling point, assuming complete dissociation?
MgCl2 dissociates into three ions (Mg2+ and 2 Cl−), giving it the highest van 't Hoff factor (i = 3) among the options, leading to the greatest boiling-point elevation.
A solution has an osmotic pressure of 5 atm at 300 K. If the temperature is increased to 350 K, what will happen to the osmotic pressure, assuming the concentration remains constant?
Osmotic pressure is directly proportional to temperature, so increasing the temperature while keeping the concentration constant will increase the osmotic pressure.
Π = M R T
Π = osmotic pressure (in atm)
M = molarity of the solution (in mol.L-1)
R = ideal gas constant = 0.0821 (in L.atm.K-1.mol-1)
T = absolute temperature (in K)
Which of the following solutions has the highest vapor pressure at a given temperature?
Pure water has the highest vapor pressure because the addition of any solute, whether electrolyte or non-electrolyte, lowers the vapor pressure of the solution.