Chem ch. 13

Certain substances such as alcohols are able to dissolve fairly readily in both polar and nonpolar solvents. Which statements correctly explain this behavior? Select all that apply. - Alcohols cause nonpolar solvents to ionize and therefore interact with them strongly. - 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. - Only the OH portion of the alcohol molecule interacts with the polar solvent. - The hydrocarbon portion of the alcohol interacts with the nonpolar solvent through dispersion forces.

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 describe the molality and molarity of a solution? Select all that apply. Multiple select question. Both molarity and molality express concentration in terms of moles of solute. The unit of molality is m. M must be calculated using the volume of the solution, not the volume of the solvent. m will change if the temperature of the solution changes. For a dilute aqueous solution molality and molarity are nearly equal.

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

Which of the following statements correctly explain the effect of a nonvolatile solute on the vapor pressure of a solution? Select all that apply. Multiple select question. Solute particles on the solution surface decrease the number of solvent particles that can escape. Vapor pressure is lowered. Solvent particles escape more easily from the solution in order to increase entropy. Vapor pressure is higher for the solution. The entropy of the solution is higher than that of the pure solvent. Solvent has less tendency to vaporize, and the vapor pressure is lowered. Solute particles in the solution push the solvent particles to the surface. More solvent particles escape, and the vapor pressure is increased.

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. Solvent has less tendency to vaporize, and the vapor pressure is lowered.

Which of the following options describe situations in which hydrogen bonding will be observed between the solute and the solvent? Select all that apply. - Solvent and solute both contain O, N, or F. - Solvent contains N, O, or F; solute contains OH or NH groups. - Solvent and solute both contain OH or NH groups. - Solvent contains OH or NH groups, solute contains N, O, or F atoms. - As long as the solvent can form hydrogen bonds, hydrogen bonding is observed between solute and solvent.

Solvent contains N, O, or F; solute contains OH or NH groups, Solvent contains N, O, or F; solute contains OH or NH groups, Solvent contains OH or NH groups, solute contains N, O, or F atoms.

Miscible

The substances are soluble in each other at any quantity

Parts by mass

mass of solute/ mass of solution

Molality (m)

mol of solute/ kg of solvent

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

Which of the following options correctly describe a solution that is in contact with undissolved solute at a given temperature? Select all that apply. Multiple select question. The solution is supersaturated. The concentration of dissolved solute will not change. No more solute is dissolving because there is undissolved solute. Undissolved solute is in equilibrium with dissolved solute. 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.,The rate at which solute is dissolving is equal to the rate at which solute particles are crystallizing from solution.

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

True: At normal pressures, gases are mutually soluble in all proportions because of the widely spaced particles of a gas.

ion-dipole forces

An ionic solute in a polar solvent An ionic solute in a polar solvent

To convert a concentration unit based on mass to one based on volume, the ______ of the solution will be required.

density

Concentrated aqueous HCl contains 38% w/w HCl. Calculate the mass of water present in 250. g of this solution.

155 g H2O

dipole-induced dipole forces

A nonpolar solute in a polar solvent A nonpolar solute in a polar solvent

ion-induced dipole forces

A nonpolar solute in a polar solvent that also contains dissolved ions A nonpolar solute in a polar solvent that also contains dissolved ions

What are the features of a nonvolatile, nonelectrolyte solute? Select all that apply. Multiple select question. A solute that dissolves but produces no ions in solution A solute that is nonpolar and therefore conducts no electric current in solution A solute that has a negligible vapor pressure at the boiling point of the solvent A solute that does not react readily

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

Which of the following statements correctly describe solutions consisting of gases and/or solids? Select all that apply. Gas-gas solutions form readily because all gases are miscible with each other. Gas-solid solutions are important as catalysts. Solid-solid solutions cannot form because the mixture of two solids will always be heterogeneous. A gas may dissolve in a solid by occupying the spaces between the solid particles.

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

Which of the following options correctly describe the effect of temperature on the solubility of a solid in a given solvent? Select all that apply. - In general, solids are more soluble at higher temperatures than at lower temperatures. - If ΔHsoln < 0, the solid will decrease in solubility as temperature increases. - All solids increase in solubility as temperature increases. - There is no clear correlation between ΔHsoln and solubility at different temperatures.

In general, solids are more soluble at higher temperatures than at lower temperatures., There is no clear correlation between ΔHsoln and solubility at different temperatures.

Which of the following statements correctly defines colligative properties? Multiple choice question. Properties of a solution that depend on the nature of the dissolved solute particles Properties of a solution that depend only on the number of dissolved solute particles Properties that are observed only for aqueous solutions Properties that depend on the number of different solutes present in solution

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

Solubility

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

Which of the following options that correctly describe Henry's law for gases? Select all that apply. Sgas = kH x Pgas - Sgas is usually expressed in units of g/L. - This law shows that the solubility of a gas increases with pressure. - Sgas is the solubility of the gas at a particular temperature. - kH is a constant that depends only on the nature of the gas. - Pgas is the partial pressure of the gas above the liquid.

This law shows that the solubility of a gas increases with pressure., Sgas is the solubility of the gas at a particular temperature., Pgas is the partial pressure of the gas above the liquid.

Which of the following options correctly describe the different ways of expressing the concentration of a solution? Select all that apply. Multiple select question. 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. Mass % is only used when both the solute and the solvent are solids. Molarity = mol of solutevolume of solvent

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.

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

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

Henry's law states that the solubility of a ______ in a solvent is directly proportional to the ______.

gas; pressure of that gas above the solution

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

low

Molarity (M)

mol of solute/ L of solution

Mole fraction (X)

mol of solute/ total no. of moles present

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 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, non-polar, dual