Exam 1

Question 1

Which of the following substances is the most soluble in water?

Answer 1

Copper (II) Sulfate (CuSO4)

Question 2

Which of the following solvents will best dissolve wax, which is a complex mixture of compounds that mostly are CH3-CH2-CH2-CH2-CH2-?

Answer 2

Pentane (CH3CH2CH2CH2CH3)

Question 3

You double the partial pressure of a gas over a liquid at constant temperature. Which of these statements is then true?

Answer 3

There are twice as many gas molecules in the liquid

Question 4

Suppose you take a solution and add more solvent, so that the original mass of solvent is doubled. You take this new solution and add more solute, so that the original mass of the solute is doubled. What happens to the molality of the final solution, compared to the original molality?

Answer 4

It is unchanged

Question 5

Which of the following actions will raise the osmotic pressure of a solution?

Answer 5

Increasing the temperature

Question 6

Which aqueous solution will have the lowest freezing point?

Answer 6

0.15 m NaCl

Question 7

A beaker of aqueous nickel sulfide was given to you by the local chemist and you put it on the window sill. After a few days, you notice that the mixture is getting thick toward the bottom. What is the nature of the aqueous nickel sulfate mixture?

Answer 7

It is a suspension

Question 8

An “emulsifying agent” is a compound that helps stabilize a hydrophobic colloid in a hydrophilic solvent. Which of the following choices is the best emulsifying agent?

Answer 8

CH3(CH2)10COONa

Question 9

The principal reason for the extremely low solubility of NaCl in benzene (C6H6) is due to:

Answer 9

Weak solvation of Na+ and Cl- by C6H6

Question 10

The dissolution of water in octane (C8H18) is prevented by:

Answer 10

Hydrogen bonding between water molecules

Question 11

When argon is placed in a container of neon, the argon spontaneously disperses throughout the neon because:

Answer 11

The dispersion of argon atoms produces an increase in disorder

Question 12

Hydration is a specific example of the phenomenon known generally as

Answer 12

Solvation

Question 13

The phrase “like dissolves like” refers to the fact that:

Answer 13

Polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes

Question 14

When solutions of strong electrolytes in water are formed, the ions are surrounded by water molecules. These interactions are described as a case of:

Answer 14

Hydration

Question 15

Compounds composed of a salt and water combined in definite proportions are known as:

Answer 15

Hydrates

Question 16

Which of the following substances is more likely to dissolve in water?

Answer 16

HOCH2CH2OH

Question 17

Which of the following substances is least likely to dissolve in water?

Answer 17

CCl4

Question 18

Which one of the following substances is more likely to dissolve in CCl4?

Answer 18

CBr4

Question 19

Which one of the following is most soluble in water?

Answer 19

CH3OH

Question 20

Pressure has an appreciable effect on the solubility of ____ in liquids

Answer 20

Gases

Question 21

Which of the following statements is false?

Answer 21

The weaker the attraction between the solute and solvent molecules, the greater the solubility

Question 22

Which of the following choices has the compounds correctly arranged in order of increasing solubility in water? (least soluble to most soluble)

Answer 22

CCl4

Question 23

If the partial pressure of oxygen in the air a diver breathes is too great, ______

Answer 23

The urge to breathe is reduced and not enough CO2 is removed from the body

Question 24

Which of the following concentration units varies with temperature?

Answer 24

Molarity

Question 25

Of the concentration units below, only ___ uses kg of solvent in its calculation

Answer 25

molality

Question 26

A solution contains 11% by mass of sodium chloride. This means that ____

Answer 26

100 g of the solution contains 11 g of sodium chloride

Question 27

As the concentration of a solute in a solution increases, the freezing point of the solution _____ and the vapor pressure of the solution _____

Answer 27

Decreases, decreases

Question 28

Which of the following liquids will have the lowest freezing point?

Answer 28

aqueous KF (.50m)

Question 29

A burning splint will burn more vigorously in pure oxygen than in air because ____

Answer 29

Oxygen is a reactant in combustion and concentration of oxygen is higher in pure oxygen than is in air

Question 30

Of the following, all are valid units for a reaction except ____

Answer 30

mol/L

Question 31

The kinetics of the reaction below were studied and it was determined that the reaction rate did not change when the concentration of B was tripled. The reaction is _____ order in B.

Answer 31

Zero

Question 32

A reaction was found to be zero order in A. Increasing the concentration of A by a factor of 3 will cause the reaction rate to _____

Answer 32

remain constant

Question 33

A reaction A+B—->C obeys the following rate law: Rate= k+[B]^2. If [A] is doubled, how will the rate change?

Answer 33

The rate would remain the same

Question 34

As the temperature of a reaction is increased, the rate of the reaction increases because the ___

Answer 34

Reactant molecules collide more frequently and with greater energy per collision

Question 35

In the energy profile of a reaction, the species that exists at the maximum on the curve is called the ____

Answer 35

Activated complex

Question 36

In general as activation energy increases, reaction rates ____

Answer 36

Goes down regardless of whether the reaction is exothermic or endothermic

Question 37

The intermediate in the following reaction is
A+B->C+D
B+D->X

Answer 37

D

Question 38

The equilibrium-constant of the following reaction is Kc=2.1*10^-20. What can be said about this reation?

Answer 38

At equilibrium, the concentration of reactants is much greater than that of products.