Chapter 3

Which of the following options correctly describe a solution that is in contact with undissolved solute at a given temperature?

- the rate at which solute is dissolving is equal to the rate at which solute particles are crystallizing from solution. - the concentration of dissolved solute will not change. - undissolved solute is in equilibrium with dissolved solute.

Both soaps and cell membranes rely on the behavior of molecules with dual polarity. Which of the following statements correctly describe this behavior?

-A soap functions because the nonpolar "tails" of the molecules bond to grease and the polar "heads" carry the grease into the solvent. -The lipid molecules that make up a cell membrane have a nonpolar hydrocarbon portion and a polar-ionic "head." -A cell membrane maximizes contact between parts of the lipid molecules that have the most similar types of intermolecular forces.

Certain substances such as alcohols are able to dissolve fairly readily in both polar and nonpolar solvents. Which statements correctly explain this behavior?

-Alcohols have dual polarity since they possess a polar OH group as well as a nonpolar hydrocarbon portion. -Alcohols form strong interactions with both types of solvent. -The hydrocarbon portion of the alcohol interacts with the nonpolar solvent through dispersion forces.

Which of the following statements correctly relate the charge density of an ion to heat of hydration?

-As the charge on an ion increases and its radius decreases, its charge density will increase and so will the magnitude of the heat of hydration. -An ion with a higher charge density has a more negative heat of hydration than an ion of similar size but lower charge.

Which of the following statements correctly describe the molality and molarity of a solution?

-Both molarity and molality express concentration in terms of moles of solute. -For a dilute aqueous solution molality and molarity are nearly equal. -M must be calculated using the volume of the solution, not the volume of the solvent.

Which of the following statements correctly describe solutions comprising of gases and/or solids?

-Gas-gas solutions form readily because all gases are miscible with each other -A gas may dissolve in a solid by occupying the spaces between the solid particles -Gas-solid solutions are important as catalysts

Which of the following are applications of freezing point depression?

-Refining petroleum -Car antifreeze -"Salting" frozen roads -Biological antifreeze

Which of the following are applications of osmotic pressure?

-Safe delivery of nutrients or drugs intravenously -Food preservation -Regulation of bodily water volume -Absorption of water in trees

Which of the following options describe situations in which hydrogen bonding will be observed between the solute and the solvent?

-Solvent and solute both contain OH or NH groups. -Solvent contains OH or NH groups, solute contains N, O, or F atoms. -Solvent contains N, O, or F; solute contains OH or NH groups.

Which of the following statements correctly describe the behavior of solutions, suspensions, and colloids?

-The particles in a solution are evenly distributed in the solvent. -The particles in a colloid are smaller than those in a suspension. -The major factor that causes suspension, solutions, and colloids to differ is particle size.

Which of the following options correctly describe the different ways of expressing the concentration of a solution?

-To calculate mole fraction for a given mass of a reactant or product, the masses of all solution components must be known. -The unit for molality (symbol m) is mol/kg.

A solution contains 25.0 g ethanol (C2H5OH; molar mass 46.07 g/mol) in 500. g H2O (molar mass 18.02 g/mol) at 23oC. If the vapor pressure of pure H2O at this temperature is 20.57 torr, What is the vapor pressure of the solution?

20.1 torr [Psoln = χsolvent x P°solvent. Since H2O is the solvent, we use χwater for this calculation. χwater = 27.728.3 = 0.979 Psoln = 0.979 x 20.57 = 20.1 torr]

A solution contains 0.32 mol naphthalene in 5.50 mol of toluene at 32oC. Pure toluene has a vapor pressure of 41 torr at this temperature. Which of the following options correctly solve for both P and ΔP for this solution?

P = 5.500.32+5.505.500.32+5.50 x 41= 39 torr ΔP = 0.320.32+5.500.320.32+5.50 x 41 = 2.3 torr

Which of the following statements correctly defines colligative properties?

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

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.

Colloid

a dispersion of particles in a dispersing medium; particles are too small to settle out by large enough to scatter light

Solution

a homogeneous mixture where the particles are too small to be visible particles are distributed evenly in the solvent

ion-induced dipole forces

a non polar solute in a polar solvent that also contains dissolved ions

dipole-induced dipole forces

a nonpolar solute in a polar solvent

Ion-dipole forces

an ionic solute in a polar solvent

I2 (s) has a very low solubility in H2O (l) because the weak _____ forces between I2 and H2O are not strong enough to replace the _____ between the H2O molecules.

dipole-induced dipole; hydrogen bonds

If more solute is added to a solvent, more than is able to dissolve at a given temperature, a(n) _____ will be established between dissolved and undissolved solute. The rate at which solute continues to dissolve is _____ to/than the rate at which solute crystallizes from solution.

equilibrium; equal

A solution forms when the attractive_____ between the solute and solvent are_____ in strength to the solvent-solvent and solute-solute attractions and are therefore able to replace them.

forces; similar

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

Suspension

heterogeneous mixture containing particles large enough to be seen by the naked eye; particles will settle out on standing

The charge density of an ion has a significant effect on its heat of hydration. The _____ the charge on an ion and the _____ its size, the greater its attraction to the H2O molecules surrounding it and the more _____ the value of ΔHhydr of the ion.

higher; smaller; negative

parts by mass

mass of solute/ mass of solution

Molality (m)

mol of solute/ kg of solvent

mole fraction (X)

mol of solute/ total no. moles of moles present

Molarity (M)

mol of solute/L of solution

The ratio mol of solute/L of solution is called the _____ of a solution (symbol M), whereas the _____ (symbol m) of the solution is expressed as mol of solute/ kg of solvent . For an aqueous solution, these two quantities will be very similar if the solution concentration is _____.

molarity; molality; low

The function of a soap molecule arises from its dual polarity. Its ______ interacts with grease while its ______ interacts with a solvent like water to wash the grease away.

nonpolar "tail"; polar "head"

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

number; type

An alcohol possesses a(n)_____ hydroxyl (-OH) group and a(n) _____ hydrocarbon chain. Due to its _____ polarity, an alcohol is able to dissolve in both polar and nonpolar solvents.

polar; nonpolar; dual

dispersion forces

present in all solutions; principal intermolecular force when both solvent and solute are nonpolar

The most abundant component of a solution is usually called the_____ , whereas the other dissolved components are called_____

solvent; solute

Solvent

the component present in the largest amount

Solute

the component present in the smallest amount

Solubility

the maximum amount of solute that can dissolve in a fixed quantity of a particular solvent at a given temperature

Miscible

the substances are soluble in each other at any quantity

True or false: All gases are miscible with each other.

true