Question

When a thin glass tube is put into water, the water rises 1.4 cm. When the same tube is put into hexane, the hexane rises only 0.4 cm. Complete the sentences to best explain the difference.

Answer 1

Answer:

Due to differences in the nature of the adhesive force and cohesive forces in the molecules of the individual substances and the glass tube.

Explanation:

To understand why this is so, a deep understanding of adhesive and cohesive force is required.

First, what is adhesive force?

Note: Adhesive and cohesive forces are best discussed under macroscopic level.

Adhesive force is the Intermolecular forces that exist between atoms of different molecules e g the forces explain when unlike charges stick together.

Cohesive force on the other hand is the Intermolecular force that exist between atoms of the same molecules e.g the force between hydrogen bonding.

Hence to explain the case scenario above, the adhesive force between the water molecules and the glass molecules is higher than the cohesive force between the water molecules. Hence the high rise.

For the case of the Hexane, the cohesive forces between the molecules hexane is far greater then the adhesive force between the glass molecules and the hexane molecules.