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AP Chemistry Practice Quiz: Intramolecular Force and Potential Energy

Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026

Test your understanding with short quizzes. This quiz has 10 questions to check your progress.

Question 1 of 10

On a graph of potential energy versus internuclear distance for two covalently bonded atoms, what does the distance corresponding to the minimum potential energy represent?

All Questions (10)

On a graph of potential energy versus internuclear distance for two covalently bonded atoms, what does the distance corresponding to the minimum potential energy represent?

A) The equilibrium bond length

B) The bond energy

C) The activation energy of bond formation

D) The point of maximum nuclear repulsion

Correct Answer: A

According to the provided content, a potential energy versus internuclear distance graph illustrates the equilibrium bond length at the potential energy minimum.

The depth of the potential energy well on a potential energy versus internuclear distance graph is a measure of what property?

A) The core size of the atoms

B) The bond order

C) The equilibrium bond length

D) The bond energy

Correct Answer: D

The provided content states that the potential energy graph illustrates the bond energy, which is the energy required to separate the atoms. This corresponds to the depth of the potential energy well from the minimum to where the energy is zero.

Which of the following series of carbon-carbon bonds is correctly arranged in order of increasing bond length?

A) Triple bond < Double bond < Single bond

B) Single bond < Double bond < Triple bond

C) Double bond < Single bond < Triple bond

D) Triple bond < Single bond < Double bond

Correct Answer: A

The content states that higher bond orders result in shorter bonds. A single bond has a bond order of 1, a double bond has an order of 2, and a triple bond has an order of 3. Therefore, the triple bond is the shortest, and the single bond is the longest.

According to Coulomb's law, which of the following ionic compounds would have the strongest intramolecular forces of attraction?

A) A compound with +1 and -1 ions separated by a large distance.

B) A compound with +2 and -2 ions separated by a large distance.

C) A compound with +1 and -1 ions separated by a small distance.

D) A compound with +2 and -2 ions separated by a small distance.

Correct Answer: D

The content specifies that Coulomb's law explains ionic interaction strength. Stronger interactions result from larger charges and smaller distances between the ions.

Consider the bonds H-F, H-Cl, and H-Br. As the core size of the halogen atom increases from F to Cl to Br, how are the bond length and bond energy affected?

A) Bond length increases and bond energy increases.

B) Bond length decreases and bond energy decreases.

C) Bond length increases and bond energy decreases.

D) Bond length decreases and bond energy increases.

Correct Answer: C

Covalent bond length is influenced by atom core size; a larger core size (like Cl or Br compared to F) leads to a longer bond. Generally, longer bonds are weaker, meaning they have a lower bond energy (less energy is required to break them).

A nitrogen-nitrogen triple bond (N≡N) is significantly harder to break than a nitrogen-nitrogen single bond (N-N). Which statement best explains this observation?

A) The core size of nitrogen atoms is smaller in a triple bond.

B) Higher bond orders result in stronger, higher-energy bonds.

C) The internuclear distance is greater in a triple bond.

D) Coulomb's law dictates that triple bonds have larger charges.

Correct Answer: B

The provided content directly states that higher bond orders result in shorter, stronger (higher energy) bonds. A triple bond has a higher bond order than a single bond, thus it is stronger and requires more energy to break.

The ionic compound MgO has a much stronger lattice energy (a measure of interaction strength) than NaF. Given that the internuclear distances are similar, what is the primary reason for this difference?

A) The bond in MgO has a higher bond order.

B) The ions in MgO (Mg²⁺ and O²⁻) have greater charges than the ions in NaF (Na⁺ and F⁻).

C) The core sizes of Mg and O are much smaller than Na and F.

D) The potential energy minimum for MgO is at a larger internuclear distance.

Correct Answer: B

According to Coulomb's law, interaction strength is influenced by charge and distance. Since the distances are similar, the determining factor is the magnitude of the charges. MgO is composed of +2 and -2 ions, while NaF is composed of +1 and -1 ions. The larger charges in MgO lead to a much stronger interaction.

At internuclear distances significantly larger than the equilibrium bond length, the potential energy of two interacting atoms approaches zero. What does this indicate?

A) The atoms have formed a very strong bond.

B) The repulsive forces between the nuclei are at a maximum.

C) The attractive and repulsive forces are perfectly balanced.

D) The atoms are so far apart that the interaction strength is negligible.

Correct Answer: D

The potential energy graph shows that as the distance between atoms increases to infinity, the potential energy approaches zero. This represents the state where the atoms are completely separated and no longer interacting.

Which factor explains why the ionic interaction in LiF is stronger than in KF?

A) The charges on the ions are larger in LiF.

B) The Li⁺ ion is smaller than the K⁺ ion, resulting in a smaller internuclear distance.

C) The bond order of LiF is higher than KF.

D) Fluorine has a larger core size when bonded to lithium.

Correct Answer: B

Both compounds involve ions with +1 and -1 charges. According to Coulomb's law, the other factor is distance. The lithium ion (Li⁺) is smaller than the potassium ion (K⁺) because it has fewer electron shells. This smaller ionic size leads to a smaller distance between the centers of the ions in LiF, resulting in a stronger interaction.

A double bond between two oxygen atoms (O=O) is both shorter and stronger than a single bond between two oxygen atoms (O-O). This relationship is best described by which principle?

A) Coulomb's law, because the charges are larger in a double bond.

B) The principle that larger atom core sizes lead to shorter bonds.

C) The principle that higher bond orders lead to shorter and stronger bonds.

D) The potential energy minimum for a double bond occurs at a lower energy.

Correct Answer: C

The content explicitly states that for covalent bonds, higher bond orders (like a double bond compared to a single bond) result in bonds that are both shorter and stronger (have a higher bond energy).