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Chem 101 - General Chemistry I » Spring 2021 » Chapter 11 Homework Quiz

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Question #1

A solution is prepared by mixing 22 g ethylene glycol [C2H4(OH)2, molar mass = 62 g/mol] with 108 g of water. What is the mole fraction of ethylene glycol in the solution?

A. 0.17

B. none of these

C. 6.3

D. 0.056

E. 0.35

Question #2

What is the molality of a solution prepared by dissolving 8.86 g of urea, NH2CONH2, in 91.5 g of water?

A. 1.61 m

B. 0.0282 m

C. 0.0968 m

D. 0.00146 m

E. 0.0882 m

Question #3

What partial pressure of dinitrogen monoxide gas is required in order for 0.00362 g of the gas to dissolve in 11.9 mL of pure water? The Henry's law constant for dinitrogen monoxide gas is 2.4 × 10–2 mol/L⋅atm.

A. 7.3 × 10–6 atm

B. 2 × 10–6 atm

C. 3.5 × 100 atm

D. 1.1 × 100 atm

E. 2.9 × 10–1 atm

F. 3.5 × 100 atm

Question #4

The osmotic pressure of blood is 7.65 atm at 37 °C. What mass of glucose (C6H12O6, molar mass = 180.2 g/mol) is needed to prepare 2.25 L of solution for intravenous injection? The osmotic pressure of the glucose solution must equal the osmotic pressure of blood. (R = 0.082057 L ⋅ atm/mol ⋅ K)

A. 5.67 g

B. 0.698 g

C. 0.676 g

D. 122 g

E. 1.02 × 103 g

Question #5

Select the one best statement: Boiling point elevation

A. Is the change in boiling point observed when one goes to a higher elevation

B. Occurs only at sea level

C. Occurs only when ionic solids are present

D. Results from a reduction in the vapor pressure of the solution

E. Occurs only for molecular solutes

Question #6

Which of the following solutions would have the highest boiling point?

A. 0.15 m Zn(CH3COO)2

B. pure water

C. 0.35 m CH4N2O

D. 0.10 m Cr2(SO4)3

E. 0.16 m BaI2

Question #7

What is the freezing point of a 0.27 m solution of glucose, C6H12O6, in water? (Kfp for water is 1.858 °C/m.)

A. –0.50 °C

B. –1.00 °C

C. 0.25 °C

D. –0.25 °C

E. 0.50 °C

Question #8

Which of the following statements best describes what happens when a small amount of solid sodium fluoride is dissolved in water?

A. The water molecules surround each ion in the solid NaF, separating the Na ions from the F ions.

B. The solid NaF breaks apart into separate Na and F atoms by interacting with the water molecules.

C. The solid undergoes a chemical change by reacting with the water.

D. The heat from the warm water melts the solid, making it a liquid.

E. Nothing happens, because sodium fluoride is insoluble in water.

Question #9

When acetone is dissolved in water, the resulting solution becomes warm. Is this an endothermic or exothermic process?

A. Exothermic

B. Cannot tell from the information provided

C. Endothermic

Question #10

Which one of the following combinations cannot be a colloid dispersed phase / dispersing medium

A. liquid / gas

B. solid / solid

C. liquid / liquid

D. gas / gas

E. gas / liquid

Question #11

The vapor pressure of pure water at 15 °C is 12.8 mm Hg. What is the equilibrium vapor pressure of water above a mixture of 72.0 g ethanol (CH3CH2OH, molar mass = 46.07 g/mol) and 22.0 g water?

A. 7.19 mm Hg

B. 10.0 mm Hg

C. 5.61 mm Hg

D. 2.84 mm Hg

E. 12.8 mm Hg

Question #12

In general, a process that is exothermic is favorably spontaneous. When ammonium nitrate, NH4NO3, is dissolved in water, the process is endothermic yet still spontaneous. Why is this process spontaneous? Recall that there are three steps in the dissolution process. Step 1: Solute-Solute interactions must be broken. Step 2: Solvent-Solvent interactions must be broken. Step 3: Solute-Solvent interactions are formed.

A. The process of separating water molecules from water molecules (step 2) is exothermic thus favoring a spontaneous process.

B. Steps 1 and 2 are both exothermic and thus the process is spontaneous.

C. The process is spontaneous because the overall solution upon mixing is more disordered than the pure substances NH4NO3 and water (the entropy factor), even though the overall mixing process is endothermic.

D. None of these

E. The process of separating the ammonium ions from the nitrate ions in the crystal lattice of NH4NO3 (step 1) is exothermic thus favoring a spontaneous process.

Question #13

Which of the following electrolytes is likely to have a van't Hoff factor equal to 3?

A. CaI2

B. Na3PO4

C. CaI2, KCl and Na3PO4

D. KCl

E. CaI2 and KCl

Question #14

Which of the following liquids will be miscible with water in any proportions: ethanol (CH3CH2OH), carbon tetrachloride (CCl4), hexane (C6H14), and/or formic acid (HCO2H)?

A. ethanol and formic acid

B. ethanol and carbon tetrachloride

C. carbon tetrachloride, and formic acid

D. ethanol, carbon tetrachloride, and benzene

E. carbon tetrachloride and hexane

Question #15

What term is used by chemists to quantitatively describe a solution in which a relatively small amount of solute is dissolved?

A. Unsaturated

B. Supersaturated

C. Concentrated

D. Dilute

E. Saturated

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