Chemistry Study Guide (Chapter 16)

Name three factors that influence the rate at which a solute dissolves in a solvent.

Agitation, temperature, and the particle size of the solute

How does the solubility of a gas change with an increase in temperature?

As temperature increases, solubility decreases.

Which solid substance listed in table 16.1 is nearly insoluble at any temperature?

Barium sulfate

How do you make a solution less concentrated?

Dilute it with solvent.

What happens to the vapor pressure equilibrium when a nonvolatile solute is added to a pure solvent?

Equilibrium is established at a lower vapor pressure.

True or False: Molarity and molality are always the same for a solution.

False

The directly proportional relationship between the solubility of a gas in a liquid and the pressure of the gas above the liquid is known as _____.

Henry's Law

How does a solution become super saturated?

If you raise the temperature of a solution containing a small excess of solid solute, the solute dissolves. If you then allow the solution to cool slowly, the excess solute may stay dissolves at a temperature below the temperature at which it would ordinarily crystallize.

How is the decrease in vapor pressure of a solution with a nonvolatile solute related to the number of particles per formula unit of solute?

Is it proportional.

What happens to the number of moles of solute present in the solution when the volume doubles?

Moles of solute remains the same.

One mole of which substance, glucose or sodium chloride, will produce more freezing point depression when added to equal amounts of water? Why?

Sodium chloride produces more freezing point depression, 1 mole of NaCl produces 2 mol of particles.

__________ affects the solubility of any solute, but ________ affects solubility only if the solute is a gas.

Temperature, pressure

Why does oil float on water?

The oil floats on water because oil is not soluble in water.

True or False: A nonvolatile substance is one that does not vaporize easily.

True

True or False: Finely ground particles dissolve more rapidly than larger particles because finer particles expose a greater surface area to the colliding solvent molecules.

True

True or False: Molarity is the number of moles of dissolved solute per liter of solvent.

True

True or False: The solubility of sodium chloride in water increases to 39.2 g per 100 g of water at 100 degrees C from 36.2 g per 100 g of water at 25 degrees C.

True

Which of the following is a correct description of the change in molarity of a solution when the volume doubles. a. The molarity of the solution is cut in half. b. The molarity of the solution doubles. c. The molarity of the solution remains constant. d. The molarity of the solution increases slightly.

a

Select the letter of each sentence that is true about a saturated solution: a. The total amount of dissolved solute remains constant. b. The total mass of undissolved crystals remains constant. c. When the rate of solvation equals the rate of crystallization, a state of dynamic equilibrium exists. d. If more solute were added to the container, the total amount of dissolved solute would increase.

a, b, c

Select the sentences that are true concerning the boiling point of a solution formed by a liquid solvent and a nonvolatile solute. a. The boiling point is the temperature at which the vapor pressure equals atmospheric pressure. b. Adding a nonvolatile solute decreases the vapor pressure. c. Because of the decrease in vapor pressure, additional kinetic energy must be added to raise the vapor pressure of the liquid phrase to atmospheric pressure. d. The boiling point of the solution is higher than the boiling point of the pure solvent.

a, b, c, d

Select which sentence best answers the following question. How does the solubility of solid substances change as the temperature of the solvent increases? a. The solubility increases for all solids. b. The solubility increases for most solids. c. The solubility remains constant.

b

Select the sentences that are true about the freezing point of a solution formed by a liquid solvent and a nonvolatile solute. a. When a substance freezes, the arrangement of its particles become less orderly. b. The presence of a solute in water disrupts the formation of orderly patterns as the solution is cooled to the freezing point of pure water. c. More kinetic energy must be withdrawn from a solution than from a pure solvent in order for the solution to solidify. d. The freezing point of the solution is lower than the freezing point of the pure solvent.

b, c, d

The difference between the boiling point of a solution and that of the pure solvent is called the ______.

boiling point-elevation

Vapor-pressure lowering, freezing-point depression, and boiling-point elevation are all ________ properties.

colligative

Properties of a solution that depend only on the number of particles dissolved, but not the identity of solute particles in the solution, are called _____.

colligative properties

A measure of the amount of solute dissolved in a given quantity of solvent is the _____ of a solution.

concentration

Which of the following is the best procedure for making a 0.5-molar (0.50M) solution in a 1-L volumetric flask. a. Add distilled water exactly to the 1-L mark, add 0.5 mol of solute, and then agitate to dissolve the solute. b. Place 0.5 mol of solute in the flask, add distilled water to the 1-L mark, and then agitate to dissolve the solute. c. Combine 0.5 mol of water with 0.5 mol of solute in the flask, and then agitate to dissolve the solute. d. Fill the flask with distilled water until it is about half-full, add 0.5 mol of solute, agitate to dissolve the solute, and then carefully fill the flask with distilled water to the 1-L mark.

d

Which word does not belong: solute addition, elevation, freezing point, depression

elevation, when more solute is added, the freezing point of a solution is depressed.

A solute dissolves faster if it is stirred, temperature is _________, or particle size is __________.

increased, reduced

Which word does not belong: moles, molarity, mass, volume

mass, molarity is expressed as moles per volume.

If two liquids dissolve each other, they are said to be _____.

miscible

. The amount that freezing point is depressed or boiling point is elevated is proportional to the ______ of the solution.

molality

For a solution, the ration of moles of solute to mass of solvent in kilograms, represented by m, is the solution's ______.

molality

The ratio of solute to solvent is expressed as _____ or mole fraction

molality

The most important unit of concentration in chemistry is ____.

molarity (M)

Which word does not belong: saturated, mole, dissolved, solubility

mole, a saturated solution has the maximum amount of solute dissolved and has reached its solubility limit.

If a solution contains the maximum amount of solute for a given quantity of solvent at a constant temperature, it is called a(n) ____ solution.

saturated

If the temperature stays the same in a(n) _______ solution, a dynamic equilibrium exists between any undissolved solute and the solution.

saturated

The amount of a substance that dissolves in a given quantity of solvent at a constant temperature is called the substance's _____ at that temperature.

solubility

Which word does not belong: solubility, freezing point, colligative, vapor pressure

solubility; colligative properties, such as freezing-point lowering and vapor-pressure raising, are not dependent on the identity of the substance.

Assuming a solute is molecular and not ionic, the magnitude of the boiling-point elevation of the solution, ∆Tb, is directly proportional to _________.

the molal concentration of the solute (m)

Percent by ______ is the ratio of the volume of solute to the volume of solution.

volume

The number of moles of solute divided by the ________ is equal to molarity.

volume of solution in liters

Diluting a solution increases the ______ of the solution, but the amount of ______ in the solution stays the same.

volume, solute