Adhesive forces

Definition

Adhesive forces are the attractive forces between unlike molecules. They play a significant role in phenomena such as capillary action and the wetting of surfaces.

5 Must Know Facts For Your Next Test

1. Adhesive forces cause liquids to spread out over solid surfaces, a process known as wetting.
2. In the context of capillary action, adhesive forces between liquid molecules and the walls of a narrow tube draw the liquid upward.
3. Surface tension is influenced by both adhesive and cohesive forces, affecting how liquids interact with surfaces.
4. When adhesive forces are stronger than cohesive forces, a liquid will tend to wet the surface more effectively.
5. Examples of adhesive forces include water sticking to glass or dew forming on leaves.

Review Questions

• What role do adhesive forces play in capillary action?
• How do adhesive forces affect surface tension?
• Give an example where adhesive forces are stronger than cohesive forces.

Related terms

Cohesive Forces: The attractive forces between like molecules within a substance, responsible for phenomena such as surface tension.

Capillary Action:

The ability of a liquid to flow in narrow spaces without the assistance of external forces, often against gravity, due to adhesive and cohesive forces.

Surface Tension:

$$\text{The elastic-like force existing on the surface of a liquid caused by cohesive molecules attracting each other.}$$