Question

application on sublimation

Answer 1

The process of evaporation involves change from the liquid phase to the gas phase. Sublimation is the direct change from the solid phase to the gas phase. There are a number of applications of these processes.Evaporation has been used for a very long time to obtain salt from sea water. Typically, the salty water of the sea is stored in large pits from where the water evaporates, leaving salt behind. Evaporation of sweat from our body helps keep our body temperature down. Clothes are typically dried by hanging them out in the open. Film deposition on a variety of surfaces (known as substrates) is done by mixing the solute in volatile solvent and allowing the solvent to evaporate, leaving behind a film of the desired material.Sublimation is commonly used in freeze drying to preserve food products. This is the reason we find ice inside packs of frozen food. It is also used to purify chemicals.Hope this helps. 

Answer 2

Answer:

Applications of sublimation:

(1) Frost-free freezers 

They are the result of having a fan and air circulation inside the freezer. The sub-zero temperature combined with the air circulation that keeps the air arid, significantly accelerates the sublimation process. This keeps freezer walls and shelves free of ice, although ice-cubes will continually sublimate.

(2) Dye sublimation 

Often used in color printing on a variety of substrates, including paper. A small heater is used to vaporize the solid dye material, which then solidifies upon the paper. As this type of printer allows extremely fine control of the primary color ratios it is possible to obtain a good quality picture even with relatively low printer resolution, as compared to other printer types of similar resolution. Pictures can be printed onto "transfer toner" papers containing sublimation dyes which can then be permanently heat transferred to T-shirts, hats, mugs, metals, puzzles and other surfaces to create beautiful designs.

(3)Creates freeze dried substances

Sublimation is also used to create freeze-dried substances like tea, soup or drugs in a process called lyophilization, which consists of freezing a solution or suspension and heating it very slowly under medium to high vacuum—specifically, a pressure lower than the vapor pressure of the solvent at its melting point. This can be well below the melting point of water if there are organic solvents or salts in the sample being freeze-dried. The resulting solid is usually much easier to dissolve or resuspend than one that is produced from a liquid system, and the low temperatures involved cause less damage to sensitive or reactive substances.