Question 1

Which of the following statements best explains why the boiling point of iodine ($$I_2) is $$much higher than that of fluorine ($$F_2$$)?

Accepted Answer

Iodine has a larger molecular mass, leading to stronger London dispersion forces.

Question 2

Which intermolecular force is primarily responsible for the high boiling point of water ($$H_2O$$)?

Accepted Answer

Hydrogen bonding

Question 3

Given three isomers of $$C_5H_{12} (n-$$pentane, isopentane, neopentane), which has the lowest boiling point and why?

Accepted Answer

Neopentane, because it has the smallest surface area and weakest dispersion forces.

Question 4

Which of the following correctly ranks the strength of intermolecular forces from weakest to strongest?

Accepted Answer

Dispersion \u003c dipole-dipole \u003c hydrogen bonding \u003c ionic

Question 5

A sample of ethyl ether has a vapor pressure of 401 torr at $$18^	ext{o}C. If $$its molar heat of vaporization is $$26.1 	ext{ kJ mol}^{-1}$$, what is the vapor pressure at $$32^	ext{o}C$$? Use the Clausius-Clapeyron equation: $$\ln\left(\frac{P_2$}{P_1$}ight) = \frac{\Delta H_{vap}}{R}\left(\frac{1}{T_1$} - \frac{1}{T_2$}ight)$$, where $$R = 8.314 	ext{ J mol}^{-1} 	ext{K}^{-1}.$$

Accepted Answer

Approximately 700 torr

Question 6

Which property of liquids is most directly affected by the strength of intermolecular forces?

Accepted Answer

Viscosity

Question 7

Which of the following phase transitions is exothermic?

Accepted Answer

Freezing

Question 8

A 100 g sample of ice at $$-30^	ext{o}C is $$heated until it becomes steam at $$120^	ext{o}C. $$Which segment of the heating curve requires the most energy?

Accepted Answer

Vaporizing water at $$100^	ext{o}C$$

Question 9

Which type of crystalline solid is characterized by high melting points and electrical conductivity in the molten state, but not in the solid state?

Accepted Answer

Ionic solid

Question 10

What is the dominant intermolecular force in methanol ($$CH_3OH$$)?

Accepted Answer

Hydrogen bonding

Question 11

Which of the following best describes the process of capillary action in water?

Accepted Answer

It is caused by the adhesion of water molecules to the walls of a narrow tube and cohesion between water molecules.

Question 12

Which of the following statements about phase diagrams is correct?

Accepted Answer

The triple point is where solid, liquid, and gas phases coexist in equilibrium.

Question 13

Which of the following substances would you expect to have the highest viscosity at room temperature?

Accepted Answer

Glycerol

Question 14

Which equation would you use to calculate the heat required to raise the temperature of a liquid water sample from $$T_1 to$$ $$T_2$$?

Accepted Answer

$$q = m c \Delta T$$

Question 15

Which of the following best explains why ionic solids do not conduct electricity in the solid state?

Accepted Answer

Ions are fixed in place and cannot move to carry charge.

Question 16

Which of the following is true about London dispersion forces?

Accepted Answer

They are present in all molecules, but are the only IMFs in nonpolar molecules.

Question 17

Which of the following would have the highest boiling point?

Accepted Answer

NaCl

Question 18

Which type of unit cell has the highest packing efficiency?

Accepted Answer

Face-centered cubic (FCC)

Question 19

Which of the following is a correct statement about amorphous solids?

Accepted Answer

They do not have a regular repeating pattern of particles.

Question 20

Which of the following best describes the relationship between molecular weight and boiling point for nonpolar molecules?

Accepted Answer

Boiling point increases as molecular weight increases due to stronger dispersion forces.

Liquids and Solids: Intermolecular Forces and Their Effects

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