Question

(a) Which is generally stronger, intermolecular interactions or intramolecular interactions? (b) Which of these kinds of interactions are broken when a liquid is converted to a gas?

Short answer

(a) Intramolecular interactions are generally stronger than intermolecular interactions. (b) When a liquid is converted to a gas, it is the intermolecular interactions that are broken.

Step-by-step solution

Understand Intramolecular and Intermolecular Interactions

Intramolecular interactions are forces that hold atoms together within a molecule. These forces include ionic, covalent, and metallic bonds. Intermolecular interactions, on the other hand, are forces that occur between separate molecules, such as hydrogen bonding, dipole-dipole interactions, and London dispersion forces.

Comparison of Interaction Strengths

Intramolecular interactions, namely ionic, covalent, and metallic bonds, are generally stronger than intermolecular interactions. This is because intramolecular forces involve the sharing or transfer of electrons between atoms, resulting in strong bonding forces. Intermolecular forces, however, are the result of weaker electrical forces that occur between molecules, such as induced dipole-dipole interactions and van der Waals forces.

Part (a) Answer

So, intramolecular interactions are generally stronger than intermolecular interactions.

Breaking Interactions in Phase Change

When a liquid is converted to a gas, the substance undergoes a phase change. This phase change requires energy, which serves to break the intermolecular interactions that hold the molecules together in the liquid state. As these interactions are broken, the molecules gain enough energy to escape the liquid phase and become a gas.

Part (b) Answer

When a liquid is converted to a gas, it is the intermolecular interactions that are broken.