Explain why methanol has a lower boiling point (65.0^∘ C) than water (100^∘ C)

Name: Problem 7, Chapter 10: Chemistry The Molecular Science
Uploaded: 2021-07-07T19:21:08-08:00
Duration: 2 min 27 s
Channel: Nicholas Sacco
Description: Explain why methanol has a lower boiling point (65.0^∘ C) than water (100^∘ C)

step 1 Okay, so let's explain why methanol has a, or why water has a higher boiling point than methanol

Explain why methanol has a lower boiling point (65.0^∘ C)...

Key Concepts

Boiling Point

The boiling point is the temperature at which a liquid's vapor pressure equals the surrounding atmospheric pressure. It is a physical property that is influenced by the strength of the intermolecular attractions within the liquid; stronger attractions correspond to a higher boiling point because more energy is needed to separate the molecules.

Intermolecular Forces

Intermolecular forces are the attractions between molecules, including dispersion forces, dipole-dipole interactions, and hydrogen bonding. The type and strength of these forces determine many physical properties of a substance, such as its boiling point. Substances with stronger intermolecular forces typically require more energy to vaporize.

Hydrogen Bonding

Hydrogen bonding is a specific, strong type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative elements like oxygen, nitrogen, or fluorine. The ability of a molecule to form hydrogen bonds can lead to significantly higher boiling points, as these bonds create a network of attractive forces that must be overcome for the molecule to enter the gas phase.

Molecular Structure and Hydrogen Bonding Capacity

The molecular structure determines how many hydrogen bonds a molecule can form. A molecule with multiple hydrogen bonding sites can create an extensive network of bonds, which increases its boiling point by requiring more energy to break these interactions. In contrast, molecules with fewer bonding sites have less extensive networks, leading to lower boiling points.

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