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Chemistry

Spin quantum number

Subject - Theoretical ChemistryQuantum numbers characterize quantum states of a microphysical system (e.g. a complete set of quantum numbers is required for the complete characterization of a system, whereby these can have half or whole numbers. The spin quantum number s = ± 12 characterizes e.g.
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Chemistry

Reduction reactions in organic chemistry

Reduction of nitro compounds to amines: mechanismFirst, the nitro group is reduced to the nitroso group. This is followed by the reductive addition of two hydrogen atoms to the hydroxylamine. In the last step, it is reduced again, water is split off and the amine is released Reduction by metals in acidic solution does not stop the reaction at the level of the nitroso compound or the hydroxylamine.
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Chemistry

Histamine content of some foods

Occasionally, food monitoring detects extreme values ​​in products that have been prepared with poor hygiene. In December 2004, 3885 mg histamine / kg were detected in a tuna pizza and 6300 mg histamine / kg in a butterfish sample. A total of 15 of 442 samples were rejected. The limit value applicable in the European Union for fish and fish products of the families of mackerel fish, herring fish, anchovies, grenadier fish and sailfish is 200 mg / kg and for enzymatically matured anchovy products (anchovies) 400 mg / kg.
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Chemistry

Atomic nuclei and radioactive decay processes

Do you have problems understanding the unit atomic nuclei and radioactive decay processes? Then you may be missing the following basics: Atomic nucleus: Introduction45 min.ChemistryGeneral chemistryAtomb constructionDescription of the atomic nucleus and its particles. In addition, the notation of the nuclides and the nuclear binding forces are discussed.
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Chemistry

1,3-dipolar cycloaddition and its 3D visualization

1,3-dipolar cycloadditionThe 1,3-dipolar cycloaddition describes the addition of a 1,3-dipole to a double or multiple bond of the so-called dipolarophile with the formation of a five-membered (hetero) cycle. During this cycloaddition, the formal charges disappear and the reaction proceeds in a concerted manner, preserving the stereochemistry.
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Chemistry

Periodic table

Main groups Fig. 1 Some main groups have special names: Table 11. Main group (Ia): Alkali metals Show alkali metals 2. Main group (IIa): alkaline earth metals show alkaline earth metals 6. Main group (VIa): Chalcogens Show chalcogens 7. Main group (VIIa): Halogens Show halogens 8. Main group (VIIIa): Noble gases Show noble gases
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