CHEMISTRY GLOSSARY

aqua regia    →   zlatotopka

Aqua regia is a mixture of one volume part of nitric acid (HNO₃) and three volume parts of hydrochloric acid (HCl). Dissolving of gold in aqua regia is described by the following equation:

arginine    →   arginin

Arginine is an electrically charged amino acids with basic side chains. It is one of the least frequent amino acids. As a group the charged amino acids are important for making proteins soluble. These residues are generally located on the surface of the protein. Arginine is well designed to bind the phosphate anion, and is often found in the active centers of proteins that bind phosphorylated substrates. As a cation, arginine, as well as lysine, plays a role in maintaining the overall charge balance of a protein. Although arginine is considered an essential amino acid (it must be obtained through the diet), this is true only during the juvenile period in humans.

• Abbreviations: Arg, R
• IUPAC name: 2-amino-5-(diaminomethylideneamino)pentanoic acid
• Molecular formula: C₆H₁₄N₄O₂
• Molecular weight: 174.20 g/mol

arsenic    →   arsen

Arsenic was discovered by Albertus Magnus (Germany) in 1250. The origin of the name comes from the Greek word arsenikon meaning yellow orpiment. It is steel-grey, brittle semi-metal. Resists water, acids and alkalis. Tarnishes in air, burns in oxygen. Highly toxic by inhalation or ingestion. Arsenic is found in mispickel (arsenopyrite). Many of its compounds are deadly poison and used as weed killer and rat poison. Used in semiconductors. Some compounds, called arsenides, are used in the manufacture of paints, wallpapers and ceramics.

blanching    →   blanširanje

1. Blanching is a heat treatment of foodstuffs to partially or completely inactivate the naturally occurring enzymes prior to freezing.

2. Blanching is a washing process for coins cleaning. The black surface layer of cupric oxide is removing by dipping the coins in hot dilute sulphuric acid (w(H₂SO₄) = 10 %).

buffer    →   pufer otopina

Buffer is a solution designed to maintain a constant pH when small amounts of a strong acid or base are added. Buffers usually consist of a fairly weak acid and its salt with a strong base. Suitable concentrations are chosen so that the pH of the solution remains close to the pK_a of the weak acid.

buffer capacity    →   puferski kapacitet

Buffer capacity is number of moles of a strong acid or a strong base needed to change pH of 1 dm³ of buffer solution for pH unit.

asparagine    →   asparagin

Asparagine is neutral amino acids with polar side chains. The polar amino acids are an important class of amino acids since they provide many of the functional groups found in proteins. Asparagine is a common site for attachment of carbohydrates in glycoproteins. In general this is not very reactive residues. Asparagine is amide derivative of aspartic acid. Asparagine is not essential for humans, which means that it can be synthesized from central metabolic pathway intermediates and is not required in the diet.

• Abbreviations: Asn, N
• IUPAC name: 2,4-diamino-4-oxobutanoic acid
• Molecular formula: C₄H₈N₂O₃
• Molecular weight: 132.12 g/mol

autocatalysis    →   autokataliza

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.

carboanhidrase    →   karboanhidraze

Carboanhidrase is an enzyme that catalyzes creation or decomposition of carbonic acid, regulates proportion of carbon dioxide and carbonic acid in the blood plasma.

carbonates    →   karbonati

Carbonates are compounds composed of metal cation and carbonate anion (CO₃^2-), salts of carbonic acid.