Colligative Properties

Which of these is a correct colligative property

• Boiling point depression

• Freezing point elevation

• Vapor pressure lowering

• Vapor pressure elevation

The freezing point of a solution is ___________ that of a pure solvent

• more than

• less than

• equal to

The boiling point of a solution is ___________ that of a pure solvent

• more than

• less than

• equal to

The temperature at which the vapor pressure of the liquid phase equals atmospheric pressure is called

• Boiling point

• Melting point

• Freezing point

Solution A contains 0.1 mol of sucrose, dissolved in 500. g of water. Solution B contains 0.1 mol of sodium chloride, dissolved in 500. g of water. Which fo the following statements about theses solutions is true?

• Both solutions have the same vapor pressure.

• Solution A would boil at a higher temperature than solution B would.

• Solution A would freeze at a higher temperature than solution B would.

• Both solutions would boil at the same temperature.

Calculate the approximate boiling point (in ^oC) of a solution of 285 g of magnesium chloride in 2.0 kg of water. (K_b=0.51 ^oC/m)

• 103.1 ^oC

• 101.6 ^oC

• 102.3 ^oC

• 104.8 ^oC

A solution made by dissolving 9.81 g of a nonvolatile nonelectrolyte in 90.0 g of water boiled at 100.37 ^oC. What is the approximate molar mass of the substance? K_b=0.51 ^oC/m

• 240 g/mol

• 150 g/mol

• 79 g/mol

• 61 g/mol

Acetic acid is a weak electrolyte because it

• is miscible with water.

• forms hydronium ions in aqueous solutions

• lowers the freezing point of water.

• ionizes only slightly in aqueous solution.

Which of the following is the best representation of the precipitation reaction that occurs when aqueous solutions of sodium carbonate and calcium chloride are mixed?

• Na⁺(aq) + Cl^-(aq) --> 2NaCl (s)

• @Na⁺(aq) + CO₃^2-(aq) + Ca²⁺(aq) + 2Cl^-(aq) --> CaCO₃ (s) + 2NaCl (s)

• Ca²⁺(aq) + CO₃^2-(aq) --> CaCO₃ (s)

• No precipitation reaction occurs

Colligative properties of solutions are those properties that depend on

• the amount of solute only

• the identity of solute only

• both the identity and the amount of solute