ACS Chemistry Practice Exam 2026 – The All-in-One Guide to Exam Success!

Higher surface tension in a liquid is a result of the cohesive forces between molecules at the surface. The heat of vaporization refers to the amount of energy required to convert a unit mass of a liquid into vapor without a change in temperature. A higher heat of vaporization typically indicates stronger intermolecular forces within the liquid. Since strong intermolecular forces enhance the cohesive interactions among the surface molecules, this leads to higher surface tension.

In contrast, a liquid with lower heat of vaporization would suggest weaker intermolecular forces, which would generally lead to lower surface tension. Therefore, the relationship between higher heat of vaporization and higher surface tension is well-established, as both indicate stronger molecular attractions within the liquid.

Other options do not support higher surface tension effectively. Higher vapor pressure correlates with weaker intermolecular forces, not stronger, and thus does not contribute to higher surface tension. Lower temperature usually reduces the kinetic energy of the molecules, potentially increasing surface tension due to reduced movement, but this is not a direct cause-and-effect relationship like the heat of vaporization. Lastly, lower concentration of solutes can lead to increased surface tension in some cases, but this is context-dependent and not universally applicable as changes in solute concentration may variably affect the intermolecular forces