CHEMISTRY GLOSSARY

radioactive indicator    →   radioaktivni indikator

By use of suitable radioactive isotopes biochemical processes can be observed in plants, animals and humans, by measuring radioactive radiation of radioactive indicator. Artificial radioactive isotopes have the same chemical properties as natural ones, which enable us to mark those natural isotopes with addition of artificial ones and in this way follow the path of those elements during a chemical reaction. One of the most important radioactive indicators is the radioactive carbon ¹⁴C.

artificial radioactive isotope    →   umjetni radioaktivni izotop

Artificial radioactive isotopes are formed when an atom is bombed with an accelerator or exposing it to slow moving neutrons in a nuclear reactor. In this way isotopes (radionuclides) are obtained which are non-existent in nature because of their unstability and radioactive transition into stable isotopes. Most important radioactive isotopes are:

Radioactive isotope of cobalt is formed when ordinary metal cobalt is bombed with neutrons in a nuclear reactor.

Radioactive isotope of phosphorus is formed when ordinary phosphorus is bombed with deuterons produced in cyclotron.

radioactive isotope of carbon is formed when a nitrogen is bombed with slow moving neutrons in a nuclear reactor. It is mostly used as a radioactive indicator.

acid-base indicator    →   kiselo-bazni indikator

Acid-base indicator is a weak acid or weak base, such as litmus, methyl orange or phenolphthalein, which changes colour when it gains or loses an H⁺ ion.

indicator    →   indikator

Indicator is a substance used to show the presence of a chemical substance or ion by its colour. Acid-base indicators are compounds, such as phenolphtaleine and methyl orange, which change colour reversibly, depending on whether the solution is acidic or basic. Oxidation-reduction indicators are substances that show a reversible colour change between oxidised and reduced forms.

universal indicator    →   univerzalni indikator

Universal indicator is an indicator which undergoes several colour changes over a wide range of pH. The colour is used to indicate pH directly. Universal indicators are usually mixtures of several indicators.

radioactive series    →   radioaktivni niz

Radioactive series is a sequence of nuclides formed by successive radioactive decays until a stable decay product, the end product, is formed. A famous example of a radioactive series is the decay of uranium, which through a series of steps decays into stable lead.

artificial radioactivity    →   umjetna radioaktivnost

Artificial radioactivity is a creation, with the help of an accelerator or in the nuclear reactor, of isotopes (radionuclides) which are found in nature because they are unstable and by radioactive conversion they are converted to stable isotopes.

carbon dating    →   određivanje starosti radioaktivnim ugljikom

Carbon dating is used to the time passed since a living organism died. It is based on measuring the quantity of isotope of carbon-14 that is contained in all living organisms.

radioactivity    →   radioaktivnost

Radioactivity is capability of a spontaneous decay of an atom. In this way a new atom type is formed and radioactive radiation is released. An atom can emit three types of radioactive radiation: positive α-radiation, negative β-radiation and electrically neutral γ-radiation. During radioactive decay one element never emits all types of radiation at the same time.

indicator electrode    →   indikatorska elektroda

Indicator electrode is working in one of the electrodes in some classical two-electrode cells, e.g., in a potentiometric electroanalytical setup where the potential of the measuring electrode (against a reference electrode) is a measure of the concentration (more accurately activity) of a species in the solution.