CHEMISTRY GLOSSARY

alkenes    →   alkeni

Alkenes are acyclic branched or unbranched hydrocarbons having one or more double carbon-carbon bonds in their molecules. In the systematic chemical nomenclature, alkene names end in the suffix -ene. The general formula is C_nH_(2n+2)-2x were x is the number of double bonds. Alkenes that have only one double bond form a homologous series: ethene (ethylene), CH₂=CH₂, propene, CH₃CH₂=CH₂, etc. Alkenes typically undergo addition reactions to the double bond.

alkynes    →   alkini

Alkynes (acetylenes) are acyclic branched or unbranched hydrocarbons having one or more triple carbon-carbon bond. In the systematic chemical nomenclature alkyne names end in the suffix -yne. The general formula is C_nH_(2n+2)-4x were x is the number of triple bonds. Alkynes that have only one triple bond form a homologous series: ethyne (acetylene), CH≡CH, propyne, CH₃CH≡CH, etc. Like alkenes, alkynes undergo addition reaction.

amphoteric substances    →   amfoterna tvar

Amphoteric substances can behave as acids or as bases depending upon their surroundings. So aluminium hydroxide in reaction with acids will behave as a base

and in reaction with bases it will act as an acid

Arrhenius equation    →   Arheniusova jednadžba

In 1889, Svante Arrhenius explained the variation of rate constants with temperature for several elementary reactions using the relationship

where the rate constant k is the total frequency of collisions between reaction molecules A times the fraction of collisions exp(-E_a/RT) that have an energy that exceeds a threshold activation energy E_a at a temperature of T (in kelvin). R is the universal gas constant.

autocatalysis    →   autokataliza

Autocatalysis is a reaction in which its product can act as a catalyst. Oxalate oxidation with permanganate in an acid solution is a slow reaction

Mn²⁺-ions catalyse this reaction. When enough Mn²⁺-ions are created, the reaction occurs instantly.

chemical compound    →   kemijski spoj

Some substance is a compound only if it can be decomposed into two or more different substances by means of a chemical reaction. If two or more substances react, thus creating a new substance, that new substance is called a chemical compound.

chemical energy    →   kemijska energija

Chemical energy is the energy stored in substances and transferred during chemical reaction.

chemical equation equalization    →   izjednačavanje kemijske jednadžbe

Chemical equation equalization is determining values of stechiometric coefficients of reactants and products in a chemical equation in a way that the number of atoms of each element is equal before and after the reaction.

chemical kinetics    →   kemijska kinetika

Chemical kinetics is an area of chemistry that studies rates and mechanisms of chemical reactions.

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.