CHEMISTRY GLOSSARY

cadmium    →   kadmij

Cadmium was discovered by Friedrich Strohmeyer (Germany) in 1817. The origin of the name comes from the Latin word cadmia meaning calamine (zinc carbonate, ZnCO₃), or from the Greek word kadmeia with the same meaning. It is soft, malleable, blue-white metal. Tarnishes in air, soluble in acids, insoluble in alkalis. Boiling cadmium gives off a weird, yellow-colored vapour that is poisonous. Cadmium can cause a variety of health problems, including kidney failure and high blood pressure. Cadmium is obtained as a by product of zinc refining. The mayor use of cadmium is in electroplating of steel to protect it from corrosion. Also used to make nickel-cadmium batteries. The ability of cadmium to adsorb neutrons has made it of great importance in the design of nuclear reactors. Its compounds are found in paint pigments and a wide variety of intense colours.

carbohydrate    →   ugljikohidrat

Carbohydrates (often called carbs for short) are polyhydroxy aldehydes or ketones, or substances that yield such compounds on hydrolysis. They are also known as saccharides, a term derived from the Latin word saccharum for sugar. Carbohydrates are the most abundant class of compounds in the biological world, making up more than 50 % of the dry weight of the Earth’s biomass. Every type of food we eat can have its energy traced back to a plant. Plants use carbon dioxide and water to make glucose, a simple sugar, in photosynthesis. Other carbohydrates such as cellulose and starch are made from the glucose. Light from the sun is absorbed by chlorophyll and this is converted to the energy necessary to biosynthesize carbohydrates

The term carbohydrate was applied originally to monosaccharides, in recognition of the fact that their empirical composition can be expressed as C_x(H₂O)_y. Later structural studies revealed that these compounds were not hydrates but the term carbohydrate persists.

Carbohydrates are generally classed as either simple or complex. Simple sugars, or monosaccharides, are carbohydrates that can’t be converted into smaller subunits by hydrolysis. Complex carbohydrates are made of two (disaccharides) or more (oligosaccharides, polysaccharides) simple sugars linked together by acetal (glycosidic) bonds and can be split into the former by hydrolysis.

covering power    →   prekrivna moć

Covering power is the ability of a plating solution under a set of specified plating conditions to deposit metal on the surfaces of recesses or deep holes. This term suggests an ability to cover, but not necessarily to build up, a uniform coating.

crystallisation    →   kristalizacija

Crystallisation is process in which the melted substance from a saturated solution turns into solid substance (crystal).

diffraction grating    →   difrakcijska rešetka

Diffraction grating is a series of slits used to separate an incident wave into its component wavelengths by directionally separating their diffraction maxima.

diffusion current    →   difuzijska struja

Diffusion current (i_d) is a current which is limited by the speed of particle diffusion in an electrolyte solution.

cellulose    →   celuloza

Cellulose, (C₆H₁₀O₅)_n, is a polysaccharide that consists of a long unbranched chain of glucose units linked by (1→4)-β-glycoside bonds. Nature uses cellulose primarily as a structural material to impart strength and rigidity to plants. Leaves, grasses, and cotton are primarily cellulose. The fibrous nature of extracted cellulose has led to its use in textile industry for the production of cotton, artificial silk, etc. Cellulose also serves as raw material for the manufacture of cellulose acetate, known commercially as acetate rayon, and cellulose nitrate, known as guncotton. Gunncotton is the major ingredient in smokeless powder, the explosive propellant used in artillery shells and in ammunition for firearms.

chemical equation    →   kemijska jednadžba

Chemical equation is a way of denoting a chemical reaction using the symbol for the participating particles (atoms, molecules, ions, etc.); for example,

The single arrow is used for an irreversible reaction; double arrows are used for reversible reactions. When reactions involve different phases, it is usual to put the phase in brackets after the symbol.

The numbers a, b, c, and d, showing the relative numbers of molecules reacting, are called the stoichiometric coefficients. The convention is that stoichiometric coefficients are positive for reactants and negative for products. If the sum of the coefficients is zero, the equation is balanced.

digestion    →   digeriranje

Digestion or precipitate ageing happens when freshly formed precipitate are left, usually at a higher temperature, in a solution from which it is precipitated. It results in cleaner and bigger particles.

dilution    →   razrjeđivanje

Dilution is the action of diluting or reducing the strength or concentration of a liquid, usually by the addition of water.