CHEMISTRY GLOSSARY

aqueous solution    →   vodena otopina

Aqueous solutions are those solutions where water is the solvent. An aqueous solution found in an equation describing a chemical reaction is denoted by the state symbol, (aq).

biochemistry    →   biokemija

Biochemistry is the study of the chemistry of living organisms, especially the structure and function of their chemical components (principally proteins, carbohydrates, lipids and nucleic acids).

bioelement    →   bioelement

Bioelement is any chemical element that is found in the molecules and compounds that make up living organism.

Bronsted acid    →   Bronstedova kiselina

Brøsted acid is a material that gives up hydrogen ions in a chemical reaction.

Bronsted base    →   Bronstedova baza

Brønsted base is a material that accepts hydrogen ions in a chemical reaction.

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.

analytical balance    →   analitička vaga

Analytical balances are instruments used for precise determining mass of matter. Analytical balances are sensitive and expensive instruments, and upon their accuracy and precision the accuracy of analysis result depends. The most widely used type of analytical balances are balances with a capacity of 100 g and a sensitivity of 0.1 mg. Not one quantitative chemical analysis is possible without usage of balances, because, regardless of which analytical method is being used, there is always a need for weighing a sample for analysis and the necessary quantity of reagents for solution preparation.

The working part of the balance is enclosed in a glass-fitted case. The baseplate is usually of black glass or black slate. The beam has agate knife-edges at its extremes, supporting stirrups from which balance pans are suspended. Another agate or steel knife-edge is fixed exactly in the middle of the beam on its bottom side. This knife-edge faces downwards and supports the beam. When not in use and during loading or unloading of the pans, the balance should be arrested.

The principle of operation of a modern laboratory balance bears some resemblance to its predecessor - the equal arm balance. The older instrument opposed the torque exerted by an unknown mass on one side of a pivot to that of an adjustable known weight on the other side. When the pointer returned to the center position, the torques must be equal, and the weight was determined by the position of the moving weights.

Modern electronic laboratory balances work on the principle of magnetic force restoration. In this system, the force exerted by the object being weighed is lifted by an electromagnet. A detector measures the current required to oppose the downward motion of the weight in the magnetic field.

argon    →   argon

Argon was discovered by Lord Raleigh and Sir William Ramsay (Scotland) in 1894. The origin of the name comes from the Greek word argos meaning inactive. It is colourless and odourless noble gas. Chemically inert. It is the third most abundant element in the earth’s atmosphere and makes up about 1 %. Argon is continuously released into the air by decay of radioactive potassium-40. Pure form is obtained from fractional distillation of liquid air. Used in lighting products. It is often used in filling incandescent light bulbs. Some is mixed with krypton in fluorescent lamps. Crystals in the semiconductor industry are grown in argon atmospheres.

calorimetry    →   kalorimetrija

Calorimetry is a measurement of the amount of heat evolved or absorbed in a chemical reaction, change of state, or formation of a solution, or any other event that includes heat transfer.

caramel    →   karamel

Caramel is a dark brown substance made from sugar, used to colour and flavour food, added to some liqueur as a colouring agent.