CHEMISTRY GLOSSARY

atomic number    →   atomski broj

Atomic number (Z) is a characteristic property of an element, equal to the number of protons in the nucleus. The atomic number and the element symbol are two alternate ways to label an element. In nuclide symbols, the atomic number is a leading subscript; for example, in ₂He.

charge number    →   nabojni broj

Charge number represents ion charge of an atom or a group. It is denoted as a right superscript (Fe²⁺ or SO₄^2-).

effective nuclear charge    →   efektivni naboj jezgre

Effective nuclear charge. (Z_eff) is the nuclear charge experienced by an electron when other electrons are shielding the nucleus.

cetane number    →   cetanski broj

Cetane number is a measure of the ignition quality of diesel fuel. It denotes the volume fraction of cetane (C₁₆H₃₄) in a combustible mixture (containing cetane and 1-methylnapthalene) whose ignition characteristics match those of the diesel fuel being tested. Cetane is a collection of un-branched open chain alkane molecule that ignites very easily under compression, so it was assigned a cetane number of 100, while alpha-methyl naphthalene was assigned a cetane number of 0.

Knudsen number    →   Knudsenova značajka

Knudsen number (Kn) is a dimensionless quantity used in fluid mechanics, defined by

where λ is mean free path and l is length.

Lewis number    →   Lewisova značajka

Lewis number (Le) is a dimensionless quantity used in fluid mechanics, defined by

where a is thermal diffusivity and D is diffusion coefficient.

Mach number    →   Machova značajka

Mach number (Ma) is a dimensionless quantity used in fluid mechanics, defined by

where v is velocity and c is the speed of sound.

mass number    →   maseni broj

Mass number (A) is a characteristic property of a specific isotope of an element, equal to the sum of the number of protons and neutrons in the nucleus.

napalm    →   napalm

Napalm is petrol jelled with aluminium soaps; highly incendiary liquid used in fire bombs and flame throwers.

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.