Cryogenic fractionation is a process of separation of gases by cooling them until they enter their liquid state. Large scale gas production companies use this method to produce liquid oxygen, liquid nitrogen etc. Gases have different boiling points (the temperature at which they change from liquid to gas). Oxygen has a boiling point of -183 °C, and nitrogen a boiling point of -195.8 °C. Therefore by cooling the gas mixture to -183 °C, the oxygen can be collected as liquid and the nitrogen remains its gaseous form.
Decomposition occurs when chemical compounds are broken up into simple molecules, and even as far as their original elements. These processes are normally irreversible. An example of decomposition is when ammonium nitrate is heated. This produces nitrous oxide and water which are unable to recombine.
Desiccant dryers (air dryers) use nonconsumable chemicals such as silica gel or active alumina, and can remove almost all the moisture from compressed air by adsorbing moisture on its surface. The method of regeneration, the process of removing adsorbed water from the desiccant, is the primary distinguishing feature among the various types of desiccant dryers. There are three ways to regenerate a desiccant: with air, internal or external heaters, or a heat pump.
Mannich reaction is a process in which hydrogen atoms in organic compounds are replaced with a methyl group.
Metabolism is a sum of all chemical and physiological processes by which the body builds and maintains itself. It is a process of building the body’s molecular structures from nutrients (anabolism) and breaking them down for energy (catabolism).
Microanalysis is a sum of analytical procedures used for researching of very small quantities of matter (around 1 mg).
Mineralization is a process in which organic compounds (e.g. dead plant or animal material) are converted to inorganic compounds (e.g. nitrate, carbon dioxide).
In 1836 the British chemist John Frederic Daniell (1790-1845) proposed an improved electric cell that supplied an even current during continuous operation. Daniell cell consisted of a glass jar containing copper and zinc electrodes, each immersed in their respective acidic sulphate solutions. The two solutions were separated by a porous clay cylinder separator. It was a galvanic cell in which the spontaneous electrodissolution of zinc and electroplating of copper provided the electrical current.
Zn(s) |
→ | Zn2+ + 2e- |
+0.763 V |
Cu2+ + 2e- |
→ | Cu(s) |
+0.337 V |
Zn(s) + Cu2+ |
→← | Zn2+ + Cu(s) |
+1.100 V |
Diagenesis is the process that turns sediments into sedimentary rocks. The lithification (literally turning into stone) of the sediments is usually accomplished by a cementing agent. How the weight of the overlying material increases the grains closer together, reducing pore space and eliminating some of the contained water. This water may carry mineral components in solution, and these constituents precipitate as new minerals in the pore spaces. This causes cementation, which will then start to bind the individual particles together. Further compaction and burial may cause recrystallization of the minerals to make the rock even harder.
Diffusion is the spontaneous mixing of one substance with another when in contact or separated by a permeable membrane. Diffusion is a result of the random motions of their component atoms, molecules, ions, or other particles. Diffusion occurs most readily in gases, less so in liquids, and least in solids. The rate of diffusion is proportional to the concentration of the substance and increases with temperature. The theoretical principles are stated in Fick’s laws.
Generalic, Eni. "Spontani proces." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
Glossary
Periodic Table