Question 1

Which of the following statements best explains why oil and water do not mix?

Accepted Answer

Oil molecules are nonpolar and interact only through London forces, while water molecules are polar and interact through dipole–dipole and hydrogen bonding. The lack of shared attractive forces prevents oil from dissolving in water.

Question 2

A sample of gas occupies 4.0 L at a pressure of 2.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what will be the new volume of the gas? (Use Boyle’s Law: $$P_1V_1 = P_2V_2)$$

Accepted Answer

$$2.0\ \mathrm{L}$$

Question 3

Which intermolecular force is primarily responsible for the high boiling point of water compared to other molecules of similar size?

Accepted Answer

Hydrogen bonding

Question 4

A balloon filled with helium gas has a volume of $$3.0\ \mathrm{L} at$$ $$300\ \mathrm{K}. If $$the temperature increases to $$450\ \mathrm{K} at $$constant pressure, what is the new volume? (Use Charles’s Law: $$\frac{V_1$}{T_1$} = \frac{V_2$}{T_2$})$$

Accepted Answer

$$4.5\ \mathrm{L}$$

Question 5

Which of the following best describes the arrangement of phospholipids in a cell membrane?

Accepted Answer

A bilayer with polar heads facing the aqueous environments and nonpolar tails facing inward toward each other

Question 6

Which of the following substances would you expect to have the highest boiling point?

Accepted Answer

A molecule with strong ionic attractions

Question 7

A patient’s blood pressure is measured as 120 mmHg. What is this pressure in atmospheres? (1 atm = 760 mmHg)

Accepted Answer

$$0.158\ \mathrm{atm}$$

Question 8

Which of the following best explains why straight-chain alkanes have higher boiling points than branched alkanes with the same number of carbon atoms?

Accepted Answer

Straight-chain alkanes have more surface contact, leading to stronger London forces.

Question 9

Which of the following is an example of an amphipathic molecule and its function?

Accepted Answer

A soap molecule, which allows polar and nonpolar substances to mix

Question 10

A gas sample has a pressure of $$1.5\ \mathrm{atm}$$, a volume of $$2.0\ \mathrm{L}$$, and a temperature of $$300\ \mathrm{K}. If $$the pressure increases to $$3.0\ \mathrm{atm}$$ and the temperature increases to $$600\ \mathrm{K}$$, what is the new volume? (Use the Combined Gas Law: $$\frac{P_1V_1}{T_1$} = \frac{P_2V_2}{T_2$})$$

Accepted Answer

$$2.0\ \mathrm{L}$$

Question 11

Which attractive force is the strongest?

Accepted Answer

Ionic attraction

Question 12

Why do pharmaceutical companies often add amine or carboxylic acid groups to drug molecules?

Accepted Answer

To increase the molecule’s solubility in water by making it charged at physiological pH

Question 13

Which of the following best describes the process of hydration in the dissolution of ionic compounds in water?

Accepted Answer

Multiple water molecules surround and interact with each ion, and the sum of these ion–dipole attractions overcomes the ionic bonds.

Question 14

Which of the following statements about cholesterol in cell membranes is correct?

Accepted Answer

The OH group of cholesterol orients toward the aqueous environment, while the rest of the molecule sits in the hydrophobic interior.

Question 15

Which of the following best explains why water can dissolve table sugar (sucrose) but not oil?

Accepted Answer

Water and sucrose are both polar and can form hydrogen bonds, while oil is nonpolar and cannot interact with water’s hydrogen bonding.

Question 16

Which of the following is true about the boiling point of a liquid?

Accepted Answer

It is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure.

Question 17

Which of the following best describes the role of intermolecular forces in determining the melting point of a substance?

Accepted Answer

The stronger and more numerous the intermolecular forces, the higher the melting point.

Question 18

Which of the following is a correct application of the kinetic molecular theory to explain why gas pressure increases with temperature?

Accepted Answer

As temperature increases, gas particles move faster and collide with the container walls more frequently and with greater force.

Question 19

Which of the following best describes the function of emulsifiers such as soaps?

Accepted Answer

They allow polar and nonpolar substances to be suspended in the same mixture by having both hydrophilic and hydrophobic regions.

States of Matter and Their Attractive Forces: Gas Laws, Solubility, and Cell Membranes

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