CHEMISTRY GLOSSARY

specific weight    →   specifična težina

Specific weight (γ) is defined as the ratio between the weight of a mass element, Δm, and the volume, ΔV, occupied by that element. As density (average) is defined as the ratio of a mass element and its volume, specific weight is equal to:

where g is gravitational acceleration.

specific quantity    →   specifična veličina

Specific quantity is often convenient to express an extensive quantity (e.g., volume, enthalpy, heat capacity, etc.) as the actual value divided by mass. The resulting quantity is called specific volume, specific enthalpy, etc.

weight    →   težina

Weight is a measure of the pull of gravitation force on an object. It is directly proportional to mass.

atomic weight    →   atomska težina

See Relative atomic mass.

specific heat    →   specifični toplinski kapacitet

Specific heat is the quantity of heat required to raise the temperature of one gram of a substance by one degree Celsius.

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.

centrifuge    →   centrifuga

Centrifuge is a device in which solid or liquid particles of different densities are separated by rotating them in a tube in a horizontal circle. The dense particles tend to move along the length of the tube to a greater radius of rotation, displacing the lighter particles to the other end.

sand filtration    →   pješčana filtracija

Sand filtration is a frequently used and very robust method of removing suspended solids from water. The filtration medium consists of a multiple layer of sand with a variety in size and specific gravity. Sand filters can be supplied in different sizes and materials, both hand operated and fully automatically.

lithosphere    →   litosfera

Lithosphere (from the Greek for rocky sphere) is rigid, rocky outer layer of the Earth, consisting of the crust and the solid outermost layer of the upper mantle. The distinguishing characteristic of the lithosphere is not its composition but its flow properties. It floats on the asthenosphere, which is the heat-softened layer of the mantle below the lithosphere.

The lithospheric is not one continuous piece but is broken into about a dozen major separate rigid blocks, or plates, which move independently relative to one another. This movement of lithospheric plates over the asthenosphere is described as plate tectonics. When an oceanic plate and a continental plate meet, the heavier oceanic plate (composed mostly of basalt, specific gravity about 3.0 or peridotite, specific gravity about 3.3) subducts under the lighter continental plate (composed mostly of granite, specific gravity about 2.7).

relative density    →   relativna gustoća

Relative density (d) is the ratio of the density of a substance to the density of some reference substance. For liquids or solids it is the ratio of the density (usually at 20 °C) to the density of water at 4 °C. Since one must specify the temperature of both the sample and the water to have a precisely defined quantity, the use of this term is now discouraged. This quantity was formerly called specific gravity.