In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. b. CH₃CH₂CH₂OH or CH₃OH

Key Concepts

Vapor Pressure

Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase at a given temperature. It reflects the tendency of molecules to escape from the liquid phase into the gas phase. Compounds with weaker intermolecular forces generally exhibit higher vapor pressures because their molecules can more easily enter the vapor phase.

Intermolecular Forces

Intermolecular forces are the forces of attraction or repulsion between neighboring particles (atoms, molecules, or ions). These forces include hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Stronger intermolecular forces result in lower vapor pressures, as more energy is required for molecules to escape into the vapor phase.

Hydrogen Bonding

Hydrogen bonding is a specific type of strong dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine. In the context of alcohols, such as CH3CH2CH2OH and CH3OH, hydrogen bonding significantly influences their physical properties, including vapor pressure. The presence of more hydrogen bonds typically leads to lower vapor pressure due to the increased energy required to break these interactions.