CHEMISTRY GLOSSARY

nascent state    →   nascentno stanje

Nascent state is an especially active state of an element in a moment when it is released from a compound during chemical reaction, e.g. nascent hydrogen.

Navier-Stokes equations    →   Navier-Stokesove jednadžbe

Navier-Stokes equations are a set of complex equations for the motion of a viscous fluid subject to external forces.

liquid aggregate state    →   tekuće agregatno stanje

Liquids have a constant volume, but they do not have a constant shape. They assume the shape of a vessel they are in at the moment. It happens because molecules of liquids are still close enough to each other, the attracting forces still being very strong.

solid state    →   čvrsto agregatno stanje

Solid state is characterised by a constant shape and volume. Particles are placed very close to one another and have efect one on another with great attraction forces. Solid bodies do not assume the shape of the container in which they are put.

state of matter    →   agregatno stanje

State of matter is one of the tree physical states in which matter can exist, i.e. solid, liquid or gas. Plasma is sometimes regarded as the fourth state of matter. By means of heating a solid substance will cross to liquid state at its melting point. If we heat up a liquid and beyond, at its boiling point it will cross to gaseous state - vapour.

Gibbs free energy    →   Gibbsova slobodna energija

Gibbs free energy (G) is an important function in chemical thermodynamics, defined by

where H is the enthalpy, S the entropy, and T the thermodynamic temperature. Gibbs free energy is the energy liberated or absorbed in a reversible process at constant pressure and constant temperature. Sometimes called Gibbs energy and, in older literature, simply free energy.

Changes in Gibbs free energy, ΔG, are useful in indicating the conditions under which a chemical reaction will occur. If ΔG is negative the reaction will proceed spontaneously to equilibrium. In equilibrium position ΔG = 0.

abundance of elements    →   rasprostranjenost elemenata

Elements in nature are mostly found in different compounds and, rarely, in the free (elementary) state. In Earth’s crust the most abundant of all elements is oxygen (with 49.5 %), then silicon (25 %), aluminium (7.5 %), iron (4.7 %), calcium (3.4 %), sodium (2.6 %), potassium (2.4 %), magnesium (1.9 %) and hydrogen (1.9 %). These nine elements make up almost 99 % of the Earth’s composition.

acetylene    →   acetilen

Acetylene (ethyne) is a colourless unstable gas, C₂H₂, with a characteristic sweet odour. It is lighter than air, easily soluble in acetone (propanone) and it is explosive under high pressure.

activity    →   aktivitet

Activity (a) is a thermodynamic function used in place of concentration in equilibrium constants for reactions involving nonideal gases and solutions. For the species i activity is defined as

where a_i is the activity of the species i, c_i is its molar concentration, and f_i is a dimensionless quantity called the activity coefficient.

adrenaline    →   adrenalin

Adrenaline was the first naturally produced hormone to be isolated in its pure state. It is known as epinephrine, but its chemical name is 1-[3,4-dihydroxyphenol]-2-methylaminoethanol. Adrenaline is a hormone, produced by the medulla of the adrenal glands, that increases heart activity, improves the power and prolongs the action of muscles, and increases the rate and depth of breathing to prepare the body for "fright, flight, or fight". At the same time it inhibits digestion and excretion.