CHEMISTRY GLOSSARY

boiling point    →   vrelište

Boiling point is the temperature at which the vapour pressure of a liquid is equal to the external pressure on the liquid. The standard boiling point is the temperature at which the vapour pressure of a liquid equals standard pressure (101 325 Pa).

Bravais lattice    →   Bravaisova rešetka

Bravais lattice is a set of points constructed by translating a single point in discrete steps by a set of basis vectors. The French crystallographer Auguste Bravais (1811-1863) established that in three-dimensional space only fourteen different lattices may be constructed. All crystalline materials recognised till now fit in one of these arrangements. The fourteen three-dimensional lattices, classified by crystal system, are shown to the bottom.

Crystal system	Bravais lattices
cubic a=b=c α=β=γ=90°
	simple cubic	body-centered cubic	face-centered cubic
tetragonal a=b≠c α=β=γ=90°
	simple tetragonal	body-centered tetragonal
orthorhombic a≠b≠c α=β=γ=90°
	simple orthorhombic	base-centered orthorhombic	body-centered orthorhombic	face-centered orthorhombic
monoclinic a≠b≠c α=γ=90°≠β
	simple monoclinic	base-centered monoclinic
hexagonal a=b≠c α=β=90° γ=120°
	hexagonal
rhombohedral a=b=c α=β=γ≠90°
	rhombohedral
triclinic a≠b≠c α≠β≠γ≠90°
	triclinic

butane    →   butan

Butane is a gaseous hydrocarbon C₄H₁₀ obtained from petroleum (refinery gas or by cracking higher hydrocarbons). The fourth member of the alkane series, it has a straight chain of carbon atoms and is isomeric with 2-methylpropane, formerly called isobutene. It can easily be liquefied under pressure and is supplied into cylinders for use as a fuel gas. It is also a raw material for making buta-1, 3-diene for synthetic rubber.

calcination    →   kalciniranje

Calcination is a process of driving out crystal water from crystal salts by heating.

covalent compound    →   kovalentni spoj

Covalent compound is a compound made of molecules - not ions, such as H₂O, CH₄, Cl₂. The atoms in the compound are bound together by shared electrons. Also called a molecular compound.

battery    →   baterija

Battery a device that converts chemical energy to electrical energy. The process underlying the operation of a battery involves a chemical reaction in which electrons are transferred from one chemical species to another. This process is carried out in two half-reactions, one that involves the loss of electrons and one that involves their gain. The battery is an electrochemical cell divided in two half-cells, and reaction proceeds when these are connected together by an electrically conducting pathway. The passage of electrons from one half-cell to the other corresponds to an electric current. Each half-cell contains an electrode in contact with the reacting species. The electrode which passes electrons into the circuit when battery discharges is called anode and is negative terminal. The electrode which receives electrons is called cathode, and is the battery’s positive terminal. The electrical circuit is completed by an electrolyte, an electrically conducting substance placed between the two electrodes which carriers a flow of charge between them. In wet cells, the electrolyte is a liquid containing dissolved ions, whose motion generates an electrical current; in dry cells the electrolyte is basely solid, for example, a solid with mobile ions or porous solid saturated with an ionic solution.

benzene    →   benzen

Benzene is a colourless liquid hydrocarbon, C₆H₆, b.p. 80 °C. It is now made from petroleum by catalytic reforming (formerly obtained from coal tar). Benzene is the archetypal aromatic compound. It has an unsaturated molecule, yet will not readily undergo addition reactions. On the other hand, it does undergo substitution reactions in which hydrogen atoms are replaced by other atoms or groups.

In 1865, Friedrich August Kekulé purposed the benzene molecule structure as a hexagonal ring which consists of six carbon atoms with alternate carbon-carbon single and carbon-carbon double bond. But such a structure should be highly reactive, and so didn't account for the unreactive nature of benzene. We now know that the best representation for the structure of benzene is indeed, hexagonal, with each C-C bond distance being identical and intermediate between those for a single and double bond. The π-orbitals from each neighbouring carbon atom overlap to form a delocalised molecular orbital which extends around the ring, giving added stability and with it, decreased reactivity. That is the reason the structural formula of benzene represents as a hexagon with a circle in the center which represents the delocalized electrons.

binary solution    →   binarna otopina

Binary solution is a mixture of two liquids that are completely miscible one with another. The boiling point of binary solution depends upon the solution composition and there can be three cases:

1. the boiling points of solutions of all compositions lie between the boiling points of clean liquids

2. the boiling points of solutions of any composition lie above the boiling points of clean liquids

3. the boiling points of solutions of some compositions lie below the boiling points of clean liquids

body-centered cubic lattice    →   prostorno centrirana kubična rešetka

Body-centered cubic lattice (bcc or cubic-I), like all lattices, has lattice points at the eight corners of the unit cell plus an additional points at the center of the cell. It has unit cell vectors a = b = c and interaxial angles α=β=γ=90°.

The simplest crystal structures are those in which there is only a single atom at each lattice point. In the bcc structures the spheres fill 68 % of the volume. The number of atoms in a unit cell is two (8 × 1/8 + 1 = 2). There are 23 metals that have the bcc lattice.

body-centered orthorhombic lattice    →   prostorno centrirana ortorompska rešetka

Body-centered orthorhombic lattice (orthorhombic-I), like all lattices, has lattice points at the eight corners of the unit cell plus an additional points at the center of the cell. It has unit cell vectors a≠b≠c and interaxial angles α=β=γ=90°.