Amadeo Avogadro (1776-1856) is an Italian chemist and physicist that proposed a correct molecular explanation for Gay-Lussac’s law of combining volumes. His work provided a simple way to determine atomic weights and molecular weights of gases. He is published a theory about the movement of particles in gases that became known as Avogadro’s Law.
Avogadro’s law: Equal volumes of all gases contain equal numbers of molecules at the same pressure and temperature. The law, often called Avogadro’s hypothesis, is true only for ideal gases. It was proposed in 1811 by Italian chemist Amadeo Avogadro (1776-1856).
Avogadro constant (NA or L) is the number of elementary entities in one mole of a substance.
It has the value (6.022 045±0.000 031)×1023 mol-1.
Acheson process is an industrial process to synthesize graphite and silicon carbide (carborundum), named after its inventor the American chemist Edward Goodrich Acheson (1856-1931). In this process, a solid-state reaction between pure silica sand (SiO2) and petroleum coke (C) at very high temperature (more than 2500 °C) leads to the formation of silicon carbide under the general reaction:
While studying the effects of high temperature on carborundum, Acheson had found that silicon vaporizes at about 4150 °C, leaving behind graphitic carbon.
Autocatalysis is a reaction in which its product can act as a catalyst. Oxalate oxidation with permanganate in an acid solution is a slow reaction
Mn2+-ions catalyse this reaction. When enough Mn2+-ions are created, the reaction occurs instantly.
The Boltzmann constant (k or kB) is the physical constant describing the relationship between the thermodynamic temperature and the average kinetic energy of particles in a gas. It equals the molar gas constant R divided by the Avogadro constant NA and has the value 1.380 648 52(79)×10-23 J/K. It is named after the Austrian physicist Ludwig Eduard Boltzmann (1844-1906).
Faraday constant (F) is the electric charge of 1 mol of singly charged positive ions.
where NA is Avogadro’s constant (6.022×1023 mol-1) and e is the elementary charge (1.602×10-19 C).
Néel temperature (TN) is the critical temperature above which an antiferromagnetic substance becomes paramagnetic. The phenomenon was discovered around 1930 by the French physicist L.E.F. Néel (1904-2000).
Bronze is an alloy made primarily of copper and tin. It may contain as much as 25 % tin. Bronzes with 10 % or more tin are harder, stronger, and resistant to corrosion. As bronze weathers, a brown or green film forms on the surface. This film inhibits corrosion. Silicon or aluminium is often added to bronze to improve resistance to corrosion. Phosphorus, lead, zinc, and other metals may be added for special purposes. The alloy is hard and easily cast and is extensively used in bearings, valves and other machine parts.
Bronze was one of the first alloys developed by ancient metal workers. The Bronze Age occurred in Europe around 2200 to 700 BC. Bronze was used for weapons such as spearheads, swords, and knives. Since ancient times, bronze has been the most popular metal for casting statues and other art objects.
The term bronze has been adopted commercially for many copper-rich alloys that contain little or no tin but are similar in colour to bronze, including aluminium bronze, manganese bronze, and silicon bronze. Aluminium bronze is used to make tools and, because it will not spark when struck. Manganese bronze is actually a brass that contains manganese. It is often used to make ship propellers because it is strong and resists corrosion by sea water.
Calomel electrode is a type of half cell in which the electrode is mercury coated with calomel (Hg2Cl2) and the electrolyte is a solution of potassium chloride and saturated calomel. In the calomel half cell the overall reaction is
Table: Dependence of potential of calomel electrode upon temperature and concentration of KCl according to standard hydrogen electrode
Potential vs. SHE / V | |||
---|---|---|---|
t / °C | 0.1 mol dm-3 | 3.5 mol dm-3 | sat. solution |
15 | 0.3362 | 0.254 | 0.2511 |
20 | 0.3359 | 0.252 | 0.2479 |
25 | 0.3356 | 0.250 | 0.2444 |
30 | 0.3351 | 0.248 | 0.2411 |
35 | 0.3344 | 0.246 | 0.2376 |
Generalic, Eni. "Avogadro%2C Amadeo." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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