chem 13.5

A solute that is nonvolatile is one that has a relatively _____ vapor pressure at the boiling point of the solvent.

low

A solution containing a nonvolatile solute will have a(n) _____ vapor pressure than the pure solvent. The change in the vapor pressure is proportional to the _____ fraction of the solute in the solution.

lower, mole

As the concentration of an ionic solution increases, the particles will ______. This causes the number of particles in solution to effectively decrease, and the colligative properties of the solution become ______ ideal.

form ion pairs; less

Which of the following statements correctly describe the behavior of different types of substances in aqueous solution? Select all that apply.

-Nonelectrolytes do not produce ions -CH3COOH is a weak electrolyte -MgCl2 is a strong electrolyte and 1 mol of MgCl2 will produce 3 moles of ions

Which of the following statements correctly explain the effect of a nonvolatile solute on the vapor pressure of a solution? Select all that apply.

-Solute particles on the solution surface decrease the number of solvent particles that can escape. Vapor pressure is lowered. -The entropy of the solution is higher than that of the pure solvent. The solvent has less tendency to vaporize, and the vapor pressure is lowered.

Place the following aqueous solutions in increasing order (lowest at the top of the list) of osmotic pressure, assuming ideal behavior.

1. 0.15 m glucose 2. 0.10 m kbr 3. 0.10 m fe(no3)3 4. 0.15 m cucl2

What are the features of a nonvolatile, nonelectrolyte solute? Select all that apply.

1. A solute that dissolves but produces no ions in solution. 2. A solute that has a negligible vapor pressure at the boiling point of the solvent.

Calculate the expected boiling point of a solution containing 0.72 mol of MgCl2 in 1.00 kg of H2O if Kb = 0.512°C⋅kg/mol.

100.0°C + (2.16 × 0.512) = 101.1oC

Which of the following correctly describe a volatile substance? Select all that apply.

The more volatile a substance is, the higher its vapor pressure at a given temperature. A volatile substance evaporates fairly readily at a given temperature.

Freezing point _____ is observed for solutions containing nonvolatile solutes. The vapor pressure of a solution is _____ than that of the pure solvent, and the solution therefore freezes at a _____ temperature.

depression, lower, lower

A solution containing 1 mol of a strong electrolyte will have a(n) _____ effect on the colligative properties of the solution than 1 mol of a nonelectrolyte. A strong electrolyte will dissociate or ionize in aqueous solution, and therefore the total number of dissolved solute particles is _____ for 1 mol of a strong electrolyte than for 1 mol of a nonelectrolyte solute.

greater; greater

A solution containing a nonvolatile solute always boils at a _____ temperature than the pure solvent. The vapor pressure of the solution is _____ than the vapor pressure of the pure solvent; hence the solution must be heated to a _____ temperature in order for the vapor pressure to equal the external pressure.

higher; lower; higher

A(n) ______ solution is defined as one that obeys Raoult's law.

ideal

Two solutions that have the same ion concentration, and thus the same osmotic pressure, are said to be ______.

isotonic

A solution containing a nonvolatile solute will have a(n) ______ vapor pressure than the pure solvent. The change in the vapor pressure is proportional to the _____ fraction of the solute in the solution.

lower, mole

Colligative properties are properties of a solution that depend only on the _____ of solute particles in a given volume of solution, not on their _____.

number; type

An ideal solution is defined as a solution that ______.

obeys Raoult's law

Select all the statements that correctly describe the osmotic pressure (π) of a solution.

osmotic pressure increases with temperature(π=MRT) Osmotic pressure is directly proportional to molarity of the solution

In a concentrated solution, cations and anions can interact to form ion _____ . This phenomenon reduces the colligative properties of a solution, since it lowers the effective particle concentration.

pairs

The van't Hoff factor i is a measure of the effect of a solute on colligative properties. It is given by the ratio: a/n where a = actual number of _____ in solution and n=number of formula units dissolved in solution. For any electrolyte, i > 1 because an electrolyte _____ in solution to produce particles per 1 mol of substance than 1 mol of a nonelectrolyte.

particles, ionizes, more

If a pure solvent is separated from a solution by a semipermeable membrane, a net flow of solvent particles will occur from the ______ side of the membrane to the ______ side. This process is called osmosis and the ______ pressure (π) is the pressure that must be applied to stop the net flow of solvent.

solvent, solution, osmotic

Match each type of substance with the correct description of its behavior in solution.

strong electrolyte- shows 100% dissociation weak electrolyte- low % dissociation or ionization in aqueous solution nonelectrolyte- does not dissociate or ionize at all

How does the presence of a strong electrolyte in solution affect the colligative properties of a solution when compared to the same number of moles of a nonelectrolyte solute?

the electrolyte dissociates or ionizes to give a larger number of moles of dissolved particles, with a greater effect on the colligative properties.

A substance that has a measurable vapor pressure at a given temperature is described as being _____.

volatile

Which of the following statements correctly describe freezing point depression for a solution? Select all that apply.

ΔTf is a positive value. Freezing point depression is proportional to the molality of the solution. The freezing point constant Kf is characteristic of the solvent.

Which of the following options correctly reflect the effect of a nonvolatile solute on the boiling point of a solution? Select all that apply.

A solution boils at a higher temperature than the pure solvent. The greater concentration of the solution the higher the boiling point will be. Boiling point elevation occurs because the presence of a nonvolatile solute lowers the vapor pressure of the solvent.

Two solutions are considered to be isotonic if they ______.

have the same concentration of solute particles

In an ideal solution of a strong electrolyte, the van't Hoff factor i is equal to _____.

the number of moles of particles produced by dissociation of 1 mol of the electrolyte

Which of the following statements correctly defines colligative properties?

Properties of a solution that depend only on the number of dissolved solute particles