Download - Chapter 11 Properties of Solutions. Copyright © Houghton Mifflin Company. All rights reserved.CRS Question, 11–2 QUESTION

Chapter 11

Properties ofProperties ofSolutionsSolutions

Copyright © Houghton Mifflin Company. All rights reserved. CRS Question, 11–2

QUESTION

What is the molality of a solution of 50.0 g of propanol (CH3CH2CH2OH) in 152 mL water, if the density of water is 1.0 g/mL? 1) 5.47 m 2) 0.00547 m 3) 0.833 m 4) 0.183 m 5) None of these


ANSWER

)

1) 5.47 m

Section 11.1 Solution Composition (p. 485

Using the density, the mass of the solution is found. Don’t forget that molality has units of kg of solvent and the mass of the solute must be subtracted from the calculated mass of solution.


QUESTION

How many milliliters of 18.4 M H2SO4 are needed to prepare 600.0 mL of 0.10 M H2SO4? 1) 1.8 mL 2) 2.7 mL 3) 3.3 mL 4) 4.0 mL 5) 4.6 mL


ANSWER

3) 3.3 mL

Section 4.3 The Composition of Solutions(p. 133)

Use the dilution equation remembering that M is mol/L not mol/mL.


QUESTION

Which of the following concentration measures will change in value as the temperature of a solution changes? 1) Mass percent 2) Mole fraction 3) Molality 4) Molarity 5) All of these


ANSWER

4) Molarity

Section 11.1 Solution Composition (p. 485)

Molarity is moles per liter of solution. The volume of a solution is temperature dependent. Generally, a solution will increase in volume as temperature increases.


ANSWER (continued)

Since the amount of solute does not change with temperature, the molar concentration of a solution decreases with increasing temperature.


QUESTION

If 2.00 g of helium gas and 4.00 g of oxygen gas are mixed together what is the mole fraction of helium in the solution? 1) 0.500 2) 0.333 3) 0.800 4) 0.200 5) 0.666


ANSWER

)

3) 0.800

Section 11.1 Solution Composition (p. 485

Remember to convert grams to moles before attempting to find the mole fraction.


QUESTION

Which of the following favors the solubility of an ionic solid in a liquid solvent? 1) A large magnitude of the solvation energy of

the ions 2) A small magnitude of the lattice energy of

the solute 3) A large polarity of the solvent 4) All of these 5) None of these


ANSWER

4) All of these

Section 11.2 The Energies of Solution Formation (p. 488)

Nonpolar compounds will have little attraction to ions and will be poor solvents for ionic compounds.


QUESTION

Which of the following chemical or physical changes is an endothermic process? 1) The evaporation of water 2) The combustion of gasoline 3) The mixing of sulfuric acid and water 4) The freezing of water 5) None of these


ANSWER

T

1) he evaporation of water

Section 11.2 The Energies of Solution Formation (p. 488)

Endo meaning “in” or “inside” indicates that endothermic is the flow of heat into a system.


QUESTION

Which statement about hydrogen bonding is true?


QUESTION (continued)

1) Hydrogen bonding is the intermolecular attractive forces between two hydrogen atoms in solution.

2) The hydrogen bonding capabilities of water molecules cause CH3CH2CH2CH3 to be more soluble in water than CH3OH.

3) Hydrogen bonding of solvent molecules with a solute will not affect the solubility of the solute.

4) Hydrogen bonding interactions between molecules are stronger than the covalent bonds within the molecule.

5) Hydrogen bonding arises from the dipole moment created by the unequal sharing of electrons within certain covalent bonds within a molecule.


ANSWER

)

-

5) Hydrogen bonding arises from the dipole moment created by the unequal sharing of electrons within certain covalent bonds within a molecule.

Section 11.3 Factors Affecting Solubility (p. 492

Hydrogen bonding is a dipole dipole interaction, but one of such magnitude that it receives its own classification.


QUESTION

The lattice energy of NaI is 686 kJ/mol and its heat of solution is –7.6 kJ/mol. Calculate the hydration of energy of NaI(s). 1) +15.2 2) –678 3) –694 4) +678 5) +694


ANSWER

–

)

3) 694

Section 11.2 The Energies of Solution Formation (p. 488

The hydration energy is needed to overcome the lattice energy, breaking the ionic bonds to loosen the ions in the crystal.


QUESTION

A correct statement of Henry’s law is: 1) the concentration of a gas in solution is

inversely proportional to temperature. 2) the concentration of a gas in solution is directly

proportional to the mole fraction of solvent. 3) the concentration of a gas in solution is

independent of pressure. 4) the concentration of a gas in a solution is

inversely proportional to pressure. 5) none of these


ANSWER

)

5) none of these

Section 11.3 Factors Affecting Solubility (p. 492

Henry’s law states that the amount of a gas dissolved in a solution is directly proportional to the pressure of the gas above the solution.


QUESTION

A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution: 1) increases over time. 2) decreases over time. 3) stays the same over time. 4) Need to know which salt is in the solution to

answer this. 5) Need to know the temperature and pressure

to answer this.


ANSWER

)

2) decreases over time.

Section 11.4 The Vapor Pressures of Solutions (p. 497

The concentration of the solution increases as the water evaporates. The higher the concentration of salt, the lower the vapor pressure.


QUESTION

A solution of two liquids, A and B, shows negative deviation from Raoult’s law. This means that:



1) the molecules of A interact strongly with other A-type molecules.

2) the two liquids have a positive heat of solution.

3) molecules of A interact weakly, if at all, with B molecules.

4) the molecules of A hinder the strong interaction between B molecules.

5) molecules of A interact more strongly with B than A with A or B with B.


ANSWER

5) molecules of A interact more strongly with B than A with A or B with B.

Section 11.4 The Vapor Pressures of Solutions (p. 497)

Raoult’s Law depends on solutions being ideal, that is, the molecules of A and molecules of B do not interact.

Many solution s have near ideal behavior, but the solute(s) and solvent of every solution interact to some

degree.


QUESTION

A liquid-liquid solution is called an ideal solution if:

a. it obeys PV = nRT. b. it obeys Raoult’s law. c. solute-solute, solvent-solvent, and

solute-solvent interactions are very similar.

d. solute-solute, solvent-solvent, and solute-solvent interactions are quite different.



1) a, b, c 2) a, b, d 3) b, c 4) b, d 5) a, b, c


ANSWER

=

3) b, c

Section 11.4 The Vapor Pressures of Solutions (p. 497)

PV nRT applies only to gases.


QUESTION

All of the following are colligative properties except: 1) osmotic pressure. 2) boiling point elevation. 3) freezing point depression. 4) density elevation. 5) none of these.


ANSWER

.

--

4) density elevation

Section 11.5 Boiling Point Elevation and FreezingPoint Depression (p. 504)

Density elevation is not a term in common chemical use.


QUESTION

Which of the following will cause the calculated molar mass of a compound determined by the freezing point depression method to be greater than the true molar mass?



1) Water gets into the solvent after the freezing point of the pure solvent is determined.

2) Some of the solute molecules break apart. 3) The mass of solvent is smaller than

determined from the weighing. 4) While adding the solute, some was spilled

on the lab bench. 5) All of these


ANSWER

- -

4) While adding the solute, some was spilled on the lab bench.


Aside from the possible health hazards, spilling chemicals in the lab will generally be disastrous to

any quantitative experiment.


QUESTION

A solute added to a solvent raises the boiling point of the solution because:



1) the temperature to cause boiling must be great enough to boil not only the solvent but also the solute.

2) the solute particles lower the solvent’s vapor pressure, thus requiring a higher temperature to cause boiling.

3) the solute particles raise the solvent’s vapor pressure, thus requiring a higher temperature to cause boiling.

4) the solute increases the volume of the solution, and an increase in volume requires an increase in the temperature to reach the boiling point (derived from PV = nRT).

5) two of these are correct.


ANSWER

- -

2) the solute particles lower the solvent’s vapor pressure, thus requiring a higher temperature to cause boiling.


At the molecular level, solute molecules at the surface interfere with solvent molecules trying to reach the vapor phase. Extra energy is needed to escape.


QUESTION

A cucumber is placed in a concentrated salt solution. What will most likely happen? 1) Water will flow from the cucumber to the

solution. 2) Water will flow from the solution to the

cucumber. 3) Salt will flow into the cucumber. 4) Salt will precipitate out. 5) No change will occur.


ANSWER

)

1) Water will flow from the cucumber to the solution.

Section 11.6 Osmotic Pressure (p. 508

Water from the cucumber flows out in an attempt to bring the concentrations of ions to the same level inside and outside of the cucumber.


QUESTION

Solutions that have identical osmotic pressures are called __________ solutions. 1) hypertonic 2) isotonic 3) hypotonic 4) hemolytic 5) dyalitic


ANSWER

2) isotonic Section 11.6 Osmotic Pressure (p. 508 ) Organisms attempt to keep their cells and their surroundings in an isotonic state. This state is the most beneficial to cell function.


QUESTION

The most likely reason for colloidal dispersion is __________. 1) the Tyndall effect 2) coagulation 3) precipitation 4) emulsion formation 5) electrostatic repulsion


ANSWER

)

5) electrostatic repulsion

Section 11.8 Colloids (p. 514

The electrostatic repulsion arises from the layers of ions that form around the colloidal particles.

Download - Chapter 11 Properties of Solutions. Copyright © Houghton Mifflin Company. All rights reserved.CRS Question, 11–2 QUESTION

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