Sublimation is the process of the change of state from solid to gaseous state without passing through the liquid state. The inverse process, that is, the direct transition from the gaseous state to the solid-state is called inverse sublimation. Dry ice, Solid Iodine, and Ammonium Chloride are examples of Sublimation.
It is a much less frequent transformation of matter than evaporation or fusion, which usually requires the injection of caloric energy until reaching a variable point according to the nature of the matter, called sublimation point.
It is often used in laboratories as a phase separation method.
Examples of Sublimation
- Dry ice. Carbon dioxide (CO 2 ) can be liquefied first and then frozen, to make dry ice. And this, at room temperature, recovers its original gaseous form.
- Polar evaporation. Since at the terrestrial poles (Arctic and Antarctic) the water is frozen even below 0 ° C, part of it sublimes back into the atmosphere.
- Snow in the mountains. The perpetual snow on the mountain tops remains in a semi-solid state, from which it can return to being vapor without having to go through its liquid state, simply sublimating.
- The disappearance of naphthalene. Made of benzene rings, this material is used as a preservative in clothing, repelling moths and other animals that eat it up. Its typical white balls disappear on their own as they go from solid to gaseous.
- Arsenic treatment. When carried above 615 ° C, arsenic, traditionally solid, loses its solid form and becomes a highly poisonous gas.
- Iodine treatment. Under laboratory heating, the iodine crystals are transformed into a characteristic purple gas.
- Frost formation. At very cold ambient temperatures, water vapor will go through a process of reverse sublimation or deposition, and will form ice crystals on the glass and surfaces, known as “frost.”
- Planetary accretion. The formation of solid matter in planets and other astronomical objects is due to the inverse sublimation of the gases released in Supernovas, whose eventual pressure and temperature may force them to become solid matter.
- Corrosive gas sublimate. Some metallic gases such as mercuric chloride can inversely sublimate in the presence of other metals, using a very frequent degradation procedure in alchemical operations.
- Obtaining CO 2 by benzoic acid. The carbon dioxide present in this solid compound is released in the form of gases when subjected to certain temperatures, without going through the liquid stage first.
- Flavoring tablets. Used in bathrooms and environments that you want to perfume, they work from the gradual transformation of the solid into a gas, allowing you to cover the entire space in which they are contained.
- Obtaining sulfur flower. This is the name given to the presentation in the form of very fine sulfur powder, extremely useful in industrial processes. This is obtained through heating the element, which sublimes under certain conditions.
- Aluminum sublimation. In certain and specific industrial processes, the sublimation of aluminum occurs, which requires raising this material to more than 1000 ° C and subjecting it to certain pressure conditions that prevent its melting at lower temperatures.
- Purification of materials. In certain alloys or homogeneous mixtures that are normally in the form of solids (compounds with iodine, with sulfur, etc.), the mixture can be purified through sublimation, heating it under controlled conditions. It is a process similar to the distillation of liquids: one solid will sublimate and the other will remain in the container.
- Difference between evaporation and boiling
- Difference between Heat and Temperature
- Types of thermometer