Question

Compare the ∆Hvap values for water, isopropyl alcohol, ether, and ammonia, and order them from lowest to highest. Explain the rank order based on intermolecular attractive forces.

Accepted Answer

Step 1: Understand the concept of ∆Hvap (enthalpy of vaporization). It is the amount of energy required to convert one mole of a liquid into a gas at constant temperature and pressure. Substances with stronger intermolecular forces will have higher ∆Hvap values because more energy is needed to overcome these forces. Step 2: Identify the types of intermolecular forces present in each substance. Water (H₂O) exhibits hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Isopropyl alcohol (C₃H₈O) also exhibits hydrogen bonding, dipole-dipole interactions, and London dispersion forces, but its hydrogen bonding is weaker than water due to its molecular structure. Ether (C₂H₆O) primarily exhibits dipole-dipole interactions and London dispersion forces, as it lacks the -OH group necessary for hydrogen bonding. Ammonia (NH₃) exhibits hydrogen bonding, dipole-dipole interactions, and London dispersion forces, but its hydrogen bonding is weaker than water due to fewer hydrogen bonds per molecule. Step 3: Compare the strength of intermolecular forces. Water has the strongest hydrogen bonding due to its ability to form multiple hydrogen bonds per molecule, followed by ammonia, which can form fewer hydrogen bonds. Isopropyl alcohol has weaker hydrogen bonding than water and ammonia due to its bulkier structure, which limits hydrogen bond formation. Ether has the weakest intermolecular forces because it lacks hydrogen bonding entirely. Step 4: Predict the ∆Hvap ranking based on the strength of intermolecular forces. Substances with stronger intermolecular forces will have higher ∆Hvap values. Therefore, the order from lowest to highest ∆Hvap should be: ether \u003c isopropyl alcohol \u003c ammonia \u003c water. Step 5: Summarize the reasoning. The rank order is based on the types and strengths of intermolecular forces present in each substance. Water has the highest ∆Hvap due to its strong hydrogen bonding, followed by ammonia, which has weaker hydrogen bonding. Isopropyl alcohol has weaker hydrogen bonding than ammonia, and ether has the lowest ∆Hvap because it lacks hydrogen bonding and relies only on weaker dipole-dipole and London dispersion forces.

Compare the ∆H_vap values for water, isopropyl alcohol, ether, and ammonia, and order them from lowest to highest. Explain the rank order based on intermolecular attractive forces.

비슷한 문제에 대한 검증된 영상 답변:

주요 개념

Enthalpy of Vaporization (∆Hvap)

Intermolecular Forces

Comparative Volatility