Cohesive forces

Definition

Cohesive forces are the intermolecular attractions that hold molecules of the same substance together. These forces play a critical role in phenomena such as surface tension and capillary action.

5 Must Know Facts For Your Next Test

1. Cohesive forces are responsible for surface tension in liquids, which allows objects denser than the liquid to float if they do not break the surface.
2. In capillary action, cohesive forces work together with adhesive forces to enable liquids to rise or fall in narrow tubes.
3. Water has strong cohesive forces due to hydrogen bonding between its molecules.
4. Surface tension caused by cohesive forces can be observed when small droplets form spherical shapes.
5. Cohesive forces must be overcome for a liquid to transition into vapor, contributing to phenomena such as boiling and evaporation.

Review Questions

• What role do cohesive forces play in surface tension?
• How do cohesive and adhesive forces interact in capillary action?
• Why does water exhibit strong cohesive properties?

Related terms

Adhesive Forces: Intermolecular attractions between different substances, crucial for phenomena like capillary action.

Surface Tension: A physical property caused by cohesive forces acting at the surface of a liquid, leading it to minimize surface area.

Capillary Action: The ability of a liquid to flow in narrow spaces without external force, driven by both cohesive and adhesive forces.