Intermolecular Forces

Properties of Liquids: Viscosity and Surface Tension


Properties of Liquids: Viscosity and Surface Tension

Viscosity

The resistance of a liquid to flow is called its viscosity

Measuring viscosity

The Physical Basis of Viscosity

Surface Tension

By definition the molecules of a liquid exhibit intermolecular attraction for one another.

What happens to molecules at the surface in comparison to those in the interior of a liquid?

The overall result of this asymmetric force on surface molecules is that:

The "inward" molecular attraction forces, which must be overcome to increase the surface area, are termed the "surface tension"

Surface tension is the energy required to increase the surface area of a liquid by a unit amount

Water

Mercury

Cohesive forces bind molecules of the same type together

Adhesive forces bind a substance to a surface

For example, attractive forces (hydrogen bonding) exists between glass materials (Silicon dioxide) and water.


1996 Michael Blaber