CHEMISTRY GLOSSARY
halogens → halogeni elementi
Halogens are the elements fluorine (F) chlorine (Cl), bromine (Br), iodine (I), and astatine (At). They are non-metals, and make up part of the 17 group in the periodic table. Compounds of these elements are called halogenides or halides.
The halogens all have a strong unpleasant odour and will burn flesh. They do not dissolve well in water. The five elements are strongly electronegative. They are oxidising agents, with fluorine being the strongest and astatine being the weakest. They react with most metals and many non-metals.
Halogens form molecules which consist of atoms covalently bonded. With increasing atomic weight there is a gradation in physical properties. For example: Fluorine is a pale green gas of low density. Chlorine is a greenish-yellow gas 1.892 times as dense as fluorine. Bromine is a deep reddish-brown liquid which is three times as dense as water. Iodine is a grayish-black crystalline solid with a metallic appearance. And astatine is a solid with properties which indicate that it is somewhat metallic in character.
hemiacetal → poluacetal
Hemiacetals are organic compounds having the general formula R2C(OH)OR’ (R’ ≠ H), derived from aldehydes or ketones by formal addition of an alcohol to the carbonyl group. Hemiacetals are generally unstable compounds. In some cases however, stable cyclic hemiacetals can be readily formed, especially when 5- and 6-membered rings are possible. In this case an intramolecular OH group reacts with the carbonyl group. Glucose and many other aldoses exist as cyclic hemiacetals whereas fructose and similar ketoses exist as cyclic hemiketals. Originally, the term was confined to derivatives of aldehydes (one R = H), but it now applies equally to derivatives of ketones (neither R = H).
homologous series → homologni niz
Series of compounds which have a common general formula and in which each member differs from the next member by a constant unit, which is the methylene group (-CH2-) is called the homologous series. Members of a homologous series are called homolog.
An example of the homologous series with some of their homologs are given below. Straight chain alkanes having general formula CnH2n+2
| Structure | Name |
|---|---|
| CH4 | methane |
| CH3-CH3 | ethane |
| CH3-CH2-CH3 | propane |
| CH3-CH2CH2CH3 | butane |
| CH3-(CH2)3-CH3 | pentane |
| CH3-(CH2)4-CH3 | hexane |
| CH3-(CH2)5-CH3 | heptane |
| CH3-(CH2)6-CH3 | octane |
| CH3-(CH2)7-CH3 | nonane |
| CH3-(CH2)8-CH3 | decane |
hydrophobic interaction → hidrofobne interakcije
Hydrophobic interaction is the tendency of hydrocarbons (or of lipophilic hydrocarbon-like groups in solutes) to form intermolecular aggregates in an aqueous medium, and analogous intramolecular interactions. The name arises from the attribution of the phenomenon to the apparent repulsion between water and hydrocarbons. Use of the misleading alternative term hydrophobic bond is discouraged.
ion exchanger → ionski izmjenjivač
Ion-exchanger is a solid or liquid material containing ions that are exchangeable with other ions with a like charge that are present in a solution in which the material is insoluble. Ion-exchange resins consist of various copolymers having a cross-linked three-dimensional structure to which ionic groups have been attached.
iridium → iridij
Iridium was discovered by Smithson Tennant (England) in 1803. The origin of the name comes from the Latin word iris, meaning rainbow, because its salts are highly colored. It is heavy, brittle, white metal. Unreactive in air, water and acids. Attacked by fused NaOH. Metal ignites and burns readily. Iridium is found in gravel deposits with platinum. Used with osmium to tip gold pen points, to make crucible and special containers. Also to make alloys used for standard weights and measures and heat-resistant alloys. Also as hardening agent for platinum.
isoelectric point → izoelektrična točka
Isoelectric point (pI or IEP) is the pH of a solution or dispersion at which the net charge on the molecules or colloidal particles is zero. In electrophoresis there is no motion of the particles in an electric field at the isoelectric point. The net charge (the algebraic sum of all the charged groups present) of any amino acid, peptide or protein, will depend upon the pH of the surrounding aqueous environment. For example, alanine can have a charge of +1, 0, or -1, depending on the pH of the solution in which it is dissolved.
Citing this page:
Generalic, Eni. "Glikozidna skupina." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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