CHEMISTRY GLOSSARY

pectin    →   pektin

Pectins are complex highmolecular carbohydrates, formed mostly from galacturonic acid. They are present in many kinds of fruit and vegetable and are used in the production of fruit jellies.

aspartic acid    →   asparaginska kiselina

Aspartic acid is an electrically charged amino acids with acidic side chains. As a group the charged amino acids are relatively abundant and are generally located on the surface of the protein. Aspartic acid and glutamic acid play important roles as general acids in enzyme active centers, as well as in maintaining the solubility and ionic character of proteins. Aspartic acid (sometimes referred to as asparate depending on pH) is non-essential in mammals, being produced from oxaloacetate by transamination.

• Abbreviations: Asp, D
• IUPAC name: 2-aminobutanedioic acid
• Molecular formula: C₄H₇NO₄
• Molecular weight: 133.10 g/mol

radiography    →   radiografija

Radiography is nondestructive method of internal examination in which metal objects are exposed to a beam of X-ray or gamma radiation. Differences in thickness, density, or absorption caused by internal defects or inclusions are apparent in the shadow image produced on a fluorescent screen or photographic film placed behind the object.

refractory metal    →   vatrostalni metal

Refractory metal is a metal having an extremely high melting point, for example tungsten, molybdenum, niobium, tantalum, and rhenium

smog    →   smog

Smog is a mixture of smoke and fog. The term is used to describe city fogs in which there is a large proportion of particulate matter (tiny pieces of carbon from exhausts) and also a high concentration of sulphur and nitrogen gases.

standard mean ocean water    →   standardna prosječna oceanska voda

Standard mean ocean water (SMOW) is a standard sample of pure water of accurately known isotopic composition which is maintained by the International Atomic Energy Agency. It is used for precise calibration of density and isotopic composition measurements.

atom    →   atom

Atom is an atom is the smallest particle of an element that retains the chemical properties of the element. Rutherford-Bohr’s model represents the atom as a positively charged core of a size around 10^-14 m composed of protons (positive particles) and neutrons (neutral particles) around which negatively charged electrons circle. The number of protons and electrons are equal, so the atom is an electrically a neutral particle. Diameter of the atom is about 10^-10 m.

atom radius    →   radijus atoma

Atoms and molecules have no strict boundaries. The volume of a free atom is usually defined as that volume that contains 90 % of electron cloud. The radius of an atom represents half of interatom distance of two identical atoms which are in touch but are not interconnected either by a covalent or an ionic bond, but with a very weak van der Waals’s bond.

automatic burette    →   automatska bireta

Automatic burette is used for series of tests. It is connected with a bottle which contains the titration solution. The air is pumped into the bottle by a small rubber air pump, created the pressure in the bottle which the rises the solution to the top of burette. When the the burette is full, the valve is released, the pressure in the bottle falls and the burette automatically sets itself to zero. Work with automatic burettes is by far faster and the consumption of standard solution is smaller.

bag filter    →   vrećasti filtar

Bag filter is a unit within a mechanical system that bellows in a bag form when air flows through, cleaning the air by collecting particles of foreign matter. This system of filtering is rated the most efficient- in a range of 92 % to 95 %. Vacuum cleaner have a cloth filter bag.

Bag filter system is an economical method of liquid filtration consisting of the pressure vessel, restrainer basket and micron rated filter bag. Liquid flow is from the inside to the outside of the bag - dirt is trapped inside the bag.