Example of Sublimation Of Matter

The sublimation It is one of the changes in the state of aggregation of matter, which consists of going from the solid to the gaseous state or vice versa, without going through the liquid phase.

There are two types of sublimation:

1. Direct sublimation or progressive sublimation, is when a solid is heated and goes directly to the gaseous state.
2. Thereverse sublimation, back sublimation or deposition, is when a gas cools down and goes directly to the solid state.

There are many substances that have the characteristic of being solid, and when heated they do not pass to the liquid state, but directly gasify. This happens, for example, with iodine or sulfur. Other elements and compounds change their state of aggregation depending mainly on temperature, and in some cases, on pressure.

For example, in aluminum, if it is heated between 550 ° C and 650 ° C, it becomes a liquid state; However, if it is heated very quickly above 2000 degrees, then it goes from a solid to a gaseous state. Once the aluminum gas cools, deposition occurs in the form of crystals.

Another substance in which sublimation occurs is solid carbon dioxide, used to cool substances that require that they not be exposed to moisture, and which is better known as “dry ice”. Dry ice is carbon dioxide subjected to very low temperatures and high pressures, producing a solid that can be handled in blocks and that are very cold. By increasing its temperature to more than is –78 ° C, the solid sublimates and goes directly to the gaseous state. This gas disperses and diffuses into the atmosphere.

Sublimation is used in the mining industry to extract and purify some chemicals, such as iodine and sulfur. In laboratories it is also used to separate some substances, such as benzoic acid.

Example 1:

We have a mixture of sodium chloride (common salt) and iodine. To separate them in the laboratory, the following material is used:

1 lighter
1 grid
1 flask
1 watch glass

Ice:

The mixture of salt with iodine is placed in the flask, covered with the watch glass, on which the ice is placed. The mixture is heated in the lighter and a purplish vapor will begin to give off. This is sublimated iodine, which has gone from solid to gaseous state. When this gas touches the watch glass that is at a low temperature, it is deposited forming solid iodine crystals. This is reverse sublimation.

Example 2:

The sublimation process is also used for printing. A cold print is made on a liquid inkjet printer, which applies the image flat on a special transfer paper. Once the ink dries, together with the paper it can take the shape of an object, for example a glass or cup, which are cylindrical.

The sublimation process is done when the glass, with the transfer paper, with the solid ink, is placed on a special plate, with the shape of the glass, and the heat causes the ink to gasify (sublimation) and this gas adhere to the glass or ceramic (sublimation reverse).