Colligative Properties

Colligative properties depend on the _________ of the solute but not the __________ of the solute.

•  concentration; identity

• identity; concentration

• reactivity; nature

• nature; reactivity

Electrolytes have a greater effect on colligative properties than nonelectrolytes do because electrolytes

• are volatile

• have higher boiling points

• produce fewer moles of solute particles per mole of solvent

• produce more moles of solute particles per mole of solvent

When 26.0 g of NaCl, are dissolved in 0.5 kg of water, what is the freezing point of this solution? (K_f = 1.86 ^oC/m)

• -3.3

• 103.3

• -1.7

• -0.8

A solution contains 15.5 g of a nonelectrolyte and 200 g of water. The water freezes at -4.5° C and K_f = 1.86° C/m. What is the molar mass of the nonelectrolyte?

• 18g/mol

• 32g/mol

• 16g/mol

• 46g/mol

• 53g/mol

What concentration of ethylene glycol is needed to raise the boiling point of water by 5 degrees C? (Kb= .51 C/m)

• 1.5 m

• 2.5 m

• 9.8 m

• 205 m

What observation(s) reflect(s) colligative properties?
I. A 0.5 m NaBr soln has a higher vapor pressure than 0.5 m BaCl₂ soln.
II. A 0.5 m NaOH soln freezes at a lower T. than pure water.
III. Pure water freezes at a higher T than pure methanol.

• only I

• only II

• only III

• 1 & II

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.

Which of the following is a colligative property?

• Boiling point elevation

• Viscosity

• Surface tension

• Density

The boiling point elevation of a solution is directly proportional to the _______.

• molarity of the solution

• mole fraction of the solute

• molality of the solution

• volume of the solvent

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

• 0.1 m NaCl

• 0.1 m glucose

• 0.1 m CaCl2

• 0.1 m urea