Question

define sublimation and thermal conductivity​

Answer 1

Answer:

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Elements and compounds mainly possess three different states at various temperatures.

The transition from solid state to gaseous state requires a transition of solid-state to liquid state and liquid state to a gaseous state.

If solids possess sufficient vapour pressure at a particular temperature than they can directly sublime into the air.

Solids which have high pressure at their triple point show sublimation.

The triple point is the point at which the pressure and temperature of the substance are such that it can exist in all three states of matter simultaneously. The triple point is a characteristic point of a substance.

There are various examples of sublimation which are experienced by us in our everyday life.

Examples of Sublimation

The best example of sublimation is dry ice which is a frozen form of carbon dioxide. When dry ice gets exposed to air, dry ice directly changes its phase from solid-state to gaseous state which is visible as fog. Frozen carbon dioxide in its gaseous state is more stable than in its solid-state.

Another well-known example of sublimation is naphthalene which is an organic compound. Naphthalene is usually found in pesticides such as mothball. This organic compound sublimes due to the presence of non-polar molecules that are held by Van Der Waals intermolecular forces. At a temperature of 176F naphthalene sublimes to form vapours. It desublimates at cool surfaces to form needle-like crystals.