Question 1

Which of the following best describes the difference between intermolecular and intramolecular forces?

Accepted Answer

Intermolecular forces occur between molecules and affect physical properties, while intramolecular forces occur within molecules and affect chemical properties.

Question 2

Which of the following is NOT a type of intermolecular force?

Accepted Answer

Covalent bond

Question 3

Why does Br$_2$ exist as a liquid at room temperature while Cl$_2$ is a gas?

Accepted Answer

Br$_2$ has stronger London dispersion forces due to its larger electron cloud and higher polarizability.

Question 4

Which of the following molecules would have the highest boiling point due to London dispersion forces?

Accepted Answer

CI$_4$

Question 5

What is the primary reason that the boiling point of noble gases increases from He to Xe?

Accepted Answer

Increasing molar mass leads to stronger London dispersion forces.

Question 6

Which of the following statements about London dispersion forces is FALSE?

Accepted Answer

They are stronger in molecules with fewer electrons.

Question 7

Why does n-pentane have a higher boiling point than neopentane, even though they have the same molecular formula?

Accepted Answer

n-pentane has a more extended shape, allowing greater surface contact and stronger London dispersion forces.

Question 8

Which of the following best explains why DNA strands are held together?

Accepted Answer

Hydrogen bonds between complementary bases stabilize the double helix.

Question 9

Which factor does NOT increase the strength of London dispersion forces?

Accepted Answer

Increasing electronegativity difference

Question 10

During vaporization of water, which type of force is primarily overcome?

Accepted Answer

Intermolecular forces

Question 11

Which of the following best describes the process that leads to the formation of London dispersion forces?

Accepted Answer

Temporary fluctuations in electron distribution create instantaneous dipoles, which induce dipoles in neighboring molecules.

Question 12

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

Accepted Answer

He

Question 13

Which property is most directly related to the strength of intermolecular forces in a liquid?

Accepted Answer

Boiling point

Question 14

Which of the following is a correct statement about the physical states of Cl$_2$, Br$_2$, and I$_2$ at room temperature?

Accepted Answer

Cl$_2$ is a gas, Br$_2$ is a liquid, and I$_2$ is a solid due to increasing strength of intermolecular forces.

Question 15

Which of the following best explains why larger atoms are more polarizable?

Accepted Answer

Their electrons are farther from the nucleus and can be distorted more easily.

Question 16

Which of the following is true about the relationship between molecular shape and London dispersion forces?

Accepted Answer

Molecules with more surface area have stronger London dispersion forces.

Question 17

Which of the following is the best explanation for why the boiling point of n-nonane (C$_9$H$_{20}$) is higher than that of n-pentane (C$_5$H$_{12}$)?

Accepted Answer

n-nonane has a higher molar mass and more electrons, resulting in stronger London dispersion forces.

Question 18

Which of the following statements about phase changes is correct?

Accepted Answer

During vaporization, molecules remain intact and only intermolecular forces are broken.

Question 19

Which of the following is the most significant factor in determining the physical state (solid, liquid, gas) of a substance at room temperature?

Accepted Answer

The strength of intermolecular forces present in the substance.

Chap 12 lecture 1 study guide chem 136

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