Question

What is sublimation?
A.The change of state of a substance directly from solid to a gas without changing into a liquid state
B.The process of change of matter from the liquid state to the solid-state at a particular temperature
C.The process of change from the gaseous state to the liquid state at a particular temperature
D.All of the above

Answer 1

Hint: To answer this question, you should recall the concept of sublimation. Sublimation is defined as the changing of a substance directly from the solid to the gas state, without passing through the liquid state.

Complete step by step answer:
-This process is endothermic and occurs at a temperature and a pressure lower than the substance's triple point in its phase diagram. This pressure is the lowest pressure at which the substance can exist as a liquid.
-The opposite or reverse of sublimation is deposition, in which a substance passes directly from a gas to a solid phase. Evaporation is considered as the transition from liquid to gas if it takes place at a temperature lower than the boiling point of the liquid, and the process of boiling only occurs at the boiling point,
-When there is no such distinction within the solid-to-gas transition, it is always described as sublimation. For example, Naphthalene usually presents in pesticides such as mothballs, sublimes easily because it is made of non-polar molecules.

Hence the correct option is A.

Note:
Sublimation requires a specific amount of energy to take place. This energy is known as sublimation energy. Sublimation molar heat can be defined as the amount of energy that must be applied to one ole of solid-phase at constant pressure to convert it directly into the gas phase. The best example of sublimation is dry ice which is a frozen form of carbon dioxide. Upon exposure of this dry ice to air, it is observed that 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.