Deck 14: The Chemistry of Solutes and Solutions

Question 1

Several processes contribute to the dissolving of a solid salt such as NaCl(s) in water. A large exothermic contribution is supplied by the

A) entropy.
B) heat of mixing.
C) hydration energy.
D) lattice energy.
E) solubilization.

Answer 1

hydration energy.

Question 2

A solution with solute concentration less than the solubility is said to be ____; ____ solute will dissolve in such as solution.

A) undersaturated; more
B) undersaturated; no more
C) saturated; more
D) saturated; no more
E) supersaturated; more

Answer 2

undersaturated; more

Question 3

The ____ of a substance is defined as the maximum amount that dissolves in a given amount of solvent at a specified temperature.

A) concentration
B) solubility
C) density
D) molarity
E) lattice energy

Answer 3

solubility

Question 4

Starting with a saturated solution of sodium chloride in water at room temperature, adding solid sodium chloride will

A) increase the concentration of the solution
B) decrease the concentration of the solution
C) increase the anion concentration and decrease the cation concentration of the solution
D) decrease the anion concentration and increase the cation concentration of the solution
E) have no effect on the concentration of the solution

Question 5

Two liquids which mix together in all proportions are said to be ____; they mix because ____.

A) miscible; their intermolecular interactions are dissimilar
B) miscible; their intermolecular interactions are similar
C) miscible; their densities are dissimilar
D) immiscible; their intermolecular interactions are similar
E) immiscible; their intermolecular interactions are dissimilar

Question 6

A solution with solute concentration equal to the solubility is said to be ____; ____ solute will dissolve in such a solution.

A) undersaturated; more
B) undersaturated; no more
C) saturated; more
D) saturated; no more
E) supersaturated; more

Question 7

Which of the following represents a solution?

A) anesthesia gas
B) carbonated water
C) stainless steel
D) ocean water
E) all of these

Question 8

Salts containing only doubly or triply charged ions are often insoluble in water. This could be because

A) the ions are highly charged, and a large number of water molecules is organized around them, so DS is negative.
B) the ions are highly charged, hence the lattice energy is very large, and DH therefore tends to be negative.
C) the ions are very large, hence the lattice energy is very large, and DH is positive.
D) both a and b.
E) both a and c.

Question 9

Ethyl alcohol and water dissolve in each other in all proportions. Therefore,

A) ethyl alcohol is miscible with water
B) ethyl alcohol is immiscible with water
C) water is miscible with ethyl alcohol
D) water is immiscible with ethyl alcohol
E) both a and c are correct

Question 10

The overall enthalpy change during the process of forming a solution involves three terms: separating solvent molecules (DH ^$\circ$ _solvent), separating solute particles (DH ^$\circ$ _solute), and forming new solute-solvent associations (DH ^$\circ$ _solution). The overall process of forming a solution is endothermic if

A) |DH ^$\circ$ _solute + DH ^$\circ$ _solvent| > |DH ^$\circ$ _solution|.
B) |DH ^$\circ$ _solute + DH ^$\circ$ _solvent| = |DH ^$\circ$ _solution|.
C) |DH ^$\circ$ _solute + DH ^$\circ$ _solvent| < |DH ^$\circ$ _solution|.
D) DH ^$\circ$ _solute + DH ^$\circ$ _solvent = 0.
E) DH ^$\circ$ _solution = 0.

Question 11

Solutions form when efficient intermolecular forces can form between solvent molecules and solute molecules or ions. What kind of intermolecular forces could be responsible?

A) dipole-dipole
B) ion-dipole
C) London
D) hydrogen bonds
E) any of a, b, c, or d

Question 12

When a solution is supersaturated the concentration of the solute is ____ the solubility, and ____ solute will dissolve.

A) less than; more
B) equal to; no more
C) greater than; more
D) less than; no more
E) greater than; no more

Question 13

If two liquids are miscible, they ____ because ____.

A) mix together; their intermolecular interactions are similar
B) do not mix together; their intermolecular interactions are similar
C) do not mix together; their intermolecular interactions are dissimilar
D) mix together; their intermolecular interactions are dissimilar
E) do not mix together; their densities are dissimilar

Question 14

The process of dissolving is favored if the ____ interactions are weaker than the ____ interactions.

A) solute-solvent; solute-solute and solvent-solvent
B) solvent-solvent; solute-solute and solute-solvent
C) solute-solute and solvent-solvent; solute-solvent
D) solute-solvent and solvent-solvent; solute-solute
E) solute-solute; solute-solvent and solvent-solvent

Question 15

If a liquid is miscible with water, some part of the molecule is ____ and therefore ____.

A) nonpolar; hydrophobic
B) nonpolar; hydrophilic
C) bipolar; insoluble
D) polar; hydrophilic
E) polar; hydrophobic

Question 16

The process of forming a solution occurs in three parts: separating solvent molecules, separating solute particles, and forming new solute-solvent associations. These three processes are, respectively,

A) endothermic, endothermic, and endothermic.
B) endothermic, endothermic, and exothermic.
C) endothermic, exothermic, and endothermic.
D) exothermic, exothermic, and endothermic.
E) exothermic, exothermic, and exothermic.

Question 17

Which of the following represents a type of solution?

A) gas in gas
B) gas in liquid
C) solid in solid
D) solid in liquid
E) all of these

Question 18

Which of the following is correct?

A) substances with similar noncovalent forces are likely to be soluble in each other
B) solutes do not readily dissolve in solvents whose noncovalent forces are quite different from their own
C) weaker solute-solvent attractions favor solubility
D) stronger solute-solute and stronger solvent-solvent attractions reduce solubility
E) a, b and d are correct

Question 19

Thermal pollution affects fish and other marine wildlife by

A) increasing the growth of marine plants.
B) increasing the uptake of toxic metals.
C) raising the body temperature of fish to a dangerous level.
D) decreasing the solubility of oxygen in water.
E) hindering the growth of marine plants.

Question 20

Sand is insoluble in both polar and nonpolar solvents because

A) the interactions between the particles of sand are much stronger than the interactions between nonpolar molecules.
B) the interactions between the particles of sand are much weaker than the interactions between polar molecules.
C) the interactions between the particles of sand are much weaker than the interactions between nonpolar molecules.
D) the interactions between the particles of sand are much stronger than the interactions between polar molecules.
E) its atoms are held together by a three-dimensional network of strong covalent bonds.

Question 21

Molarity (M) is defined as moles of solute per ____ of ____.

A) mole; solution
B) kg; solvent
C) kg; solution
D) L; solvent
E) L; solution

Question 22

Calculate the concentration in ppm of Cd in a 2.00 mL sample which has been shown to contain 16.4 mg Cd. Assume the sample has a density of 1.00 g/mL.

A) 8.20 × 10^-3
B) 8.20
C) 32.8
D) 8.20 × 10³
E) 3.28 × 10⁴

Question 23

Which units for concentration are not defined in terms of the mass or volume of any substance?

A) molarity
B) mole fraction
C) molality
D) parts per million
E) weight %

Question 24

At a particular temperature, as the pressure increases the solubility of a gas in water will

A) always decrease
B) always increase
C) remain the same
D) be inversely proportional to the pressure
E) be directly proportional to the temperature

Question 25

Molality (m) is defined as moles of solute per ____ of ____.

A) mole; solution
B) kg; solvent
C) kg; solution
D) L; solvent
E) L; solution

Question 26

For inorganic compounds, solubility in water is

A) always increased by an increase in temperature
B) always decreased by an increase in temperature
C) usually decreased by an increase in temperature
D) usually increased by an increase in temperature
E) not affected by a change in temperature

Question 27

Which of the following refers to a specific value of concentration at a given temperature?

A) saturated
B) unsaturated
C) supersaturated
D) concentrated
E) immiscible

Question 28

Assuming that its density is 1.000 g/mL, what is the mass % concentration of a 0.1432 M AgNO₃ solution?

A) 2.864 %
B) 2.433 %
C) 2.204 %
D) 1.974 %
E) 1.432 %

Question 29

The concentration unit one part per billion (one ppb) is equivalent to one ____ of solute per ____ of solution.

A) g
B) mm
C) mg
D) kg

Question 30

Increasing the temperature of water containing a dissolved gas will almost always

A) decrease the solubility of the gas
B) increase the solubility of the gas
C) have no effect on the solubility of the gas
D) decrease the solubility of the gas only if the gas is one that naturally occurs in the atmosphere
E) increase the solubility of the gas only if the gas is one that naturally occurs in the atmosphere

Question 31

Determine the chloride ion concentration in a solution containing 50.0 g MgCl₂ dissolved in 1500 mL of solution.

A) 0.350 M
B) 0.700 M
C) 1.40 M
D) 3.17 M
E) 6.34 M

Question 32

Isotonic saline solution has a mass % NaCl concentration of 0.900 %. Assuming its density is 1.00 g/mL, what is its molarity?

A) 9.00 × 10^-3 M
B) 0.0900 M
C) 0.154 M
D) 0.900 M
E) 1.80 M

Question 33

Which unit of concentration is dependent on temperature?

A) mole%
B) ppm
C) molality
D) molarity
E) mass%

Question 34

If 750. mL of a certain solution contains 50.0 g Na₂SO₄, the sodium ion concentration, [Na⁺], is

A) 0.264 M
B) 0.315 M
C) 0.469 M
D) 0.560 M
E) 0.939 M

Question 35

The pressure inside a soda bottle is two atmospheres (1520 mm Hg). If exactly half this pressure is generated by CO₂, what is the solubility of carbon dioxide in a 2 L bottle of root beer at 40 ^$\circ$ C? The Henry's Law constant for CO₂ is 4.45 × 10^-5 M/mm Hg.

A) 2.93 × 10^-8 M
B) 9.90 × 10^-5 M
C) 1.78 × 10^-3 M
D) 0.0338 M
E) 0.0676 M

Question 36

When a soda bottle is opened, there is rapid bubbling of gas; the solubility of a gas in a liquid decreases if the pressure of the gas is decreased. This is because

A) the pressure decrease is always accompanied by a temperature decrease.
B) a increase in temperature is caused by the pressure decrease.
C) the probability of collisions between the gas and the liquid surface is decreased.
D) the energy released from the bubbling process cools the gas.
E) the volume of the system must decrease if the pressure decreases.

Question 37

To convert from ____ to ____, one must multiply by ____.

A) parts per million; parts per billion; 10^-3
B) parts per thousand; parts per billion; 10³
C) parts per million; weight percent; 10^-4
D) parts per billion; parts per trillion; 10⁶
E) parts per thousand; weight percent; 10

Question 38

The solubility of a gas in a liquid is ____ the pressure of the gas; this is ____.

A) proportional to; Henry's Law
B) inversely proportional to; Henry's Law
C) proportional to; Raoult's Law
D) inversely proportional to; Raoult's Law
E) proportional to the square of; Raoult's Law

Question 39

A concentrated antifreeze solution contains 580. g ethylene glycol mixed with 540. g of water. The weight percent of water in this solution is

A) 27.0 %
B) 48.2 %
C) 51.8 %
D) 93.1 %
E) 107 %

Question 40

If 50. mL of solution containing 2.0 × 10³ ppm sodium ion is diluted to 4.0 L, what is the final concentration of sodium ion?

A) 2.5 ppm
B) 2.5 × 10⁴ ppb
C) 2.5%
D) 2.5 mg/L
E) all of these are correct

Question 41

In order to calculate the molality of a solution from its molarity, what other information would be needed?

A) molar mass of solute and molar mass of solvent
B) molar mass of solute and density of solvent
C) molar mass of solute and density of solution
D) molar mass of solvent and density of solution
E) molar mass of solvent and density of solute

Question 42

The osmotic pressure of a solution of Mg(NO₃)₂ at a given temperature is ____ that of a solution of NaNO₃ of identical concentration at the same temperature.

A) half
B) two-thirds
C) the same as
D) one and a half times
E) twice

Question 43

Explain what is meant by
a. osmosis.
b. osmotic pressure.
c. reverse osmosis.

Question 44

Osmotic pressure is the

A) pressure that must be applied to a solution in order to prevent osmosis from the pure solvent.
B) pressure that must be applied to a solution in order to cause osmosis to occur from the pure solvent.
C) correction factor applied when a sample of gas is collected by water displacement.
D) increase in vapor pressure when a solution is compared to a pure solvent.
E) decrease in vapor pressure when a solution is compared to a pure solvent.

Question 45

A coolant consisting of a 50/50 mixture by volume of ethylene glycol and water utilizes the

A) colligative properties of solutions
B) freezing point elevation constant of water
C) boiling point elevation constant of water
D) boiling point depression constant of water
E) a and c

Question 46

Given that the value of k_f for water is 1.86 ^$\circ$ C/m, what is the freezing point of an aqueous solution of NaCl prepared by mixing 427.0 g solute with 1.000 kg of water?

A) -4.36 ^$\circ$ C
B) -7.94 ^$\circ$ C
C) -13.6 ^$\circ$ C
D) -15.7 ^$\circ$ C
E) -18.3 ^$\circ$ C

Question 47

Drinkable water can be produced from seawater by the process of ____, using a membrane which is permeable to ____ but not to ____.

A) osmosis; water; ions
B) reverse osmosis; water; ions
C) reverse osmosis; sodium ions; chloride ions
D) osmosis; ions; water
E) reverse osmosis; ions; water

Question 48

The freezing points of the following aqueous solutions, from highest to lowest, are:

A) C₆H₁₂O₆ > NH₄NO₃ > CaCl₂
B) C₆H₁₂O₆ > CaCl₂ > NH₄NO₃
C) CaCl₂ > C₆H₁₂O₆ > NH₄NO₃
D) CaCl₂ > NH₄NO₃ > C₆H₁₂O₆
E) NH₄NO₃ > C₆H₁₂O₆ > CaCl₂

Question 49

The driving force for osmosis is

A) temperature.
B) pressure.
C) identity of the solute.
D) enthalpy.
E) entropy.

Question 50

In living systems, a solution with a higher solute concentration than the surrounding cells is said to be ____. This causes water to flow ____ the cells by osmosis.

A) hypertonic; into
B) hypertonic; out of
C) catatonic; into
D) hypotonic; into
E) hypotonic; out of

Question 51

What is the vapor pressure of a 45.0 % solution of glucose, C₆H₁₂O₆, at 90.0 ^$\circ$ C, given that the vapor pressure of pure water at that temperature is 526 mm Hg?

A) 486 mm Hg
B) 289 mmHg
C) 237 mm Hg
D) 78.2 mm Hg
E) 39.8 mm Hg

Question 52

A 0.1 M solution of Na₂SO₄ contains

A) 9.6 × 10³ mg/L SO₄^2-
B) 4.6 × 10⁶ ppb Na⁺
C) 14.2. g/L sodium sulfate
D) 0.3 mol/L ions
E) all of these are correct

Question 53

Consider these three primary alcohols:
The three alcohols have similar molecular structures. However, their solubilities in water decrease dramatically, in the order shown. Explain this.

Question 54

The solubility in water of magnesium fluoride, MgF₂, is 7.3 mg/100 mL. Is a solution containing 33 mg MgF₂ in 475 mL water unsaturated, saturated, or supersaturated? Show a calculation to support your answer.

Question 55

Calculate the boiling point of a mixture where 95.0 g of formic acid, H₂CO₂, is dissolved in 250 g of acetic acid. Acetic acid has a K_b of 2.93 ^$\circ$ C/m and boils at 118 ^$\circ$ C. Assume that formic acid does not ionize when dissolved in acetic acid, and that formic acid is non-volatile.

A) 118 ^$\circ$ C
B) 142 ^$\circ$ C
C) 136 ^$\circ$ C
D) 115 ^$\circ$ C
E) 126 ^$\circ$ C

Question 56

An aqueous solution of phosphoric acid, H₃PO₄, contains 285 g H₃PO₄ in 400 mL solution, and has a density of 1.35 g/mL. Calculate
a. the weight % in this solution.
b. The concentration in mol/L of this solution.

Question 57

An aqueous solution at 27 ^$\circ$ C contains 3.60 g of a protein in a 200. mL sample. The osmotic pressure is 0.0203 atm. What is the molar mass of the protein?

A) 21.8 g/mol
B) 78.6 g/mol
C) 8.70 × 10² g/mol
D) 2.03 × 10³ g/mol
E) 2.18 × 10⁴ g/mol