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The National Standard Examination in Chemistry or NSEC is an examination in chemistry for higher secondary school students in India, usually conducted in the end of November. [1] The examination is organized by the Indian Association of Chemistry Teachers. Over 30,000 students, mainly from Standard 12, sit for this examination.
This is a list of unsolved problems in chemistry. Problems in chemistry are considered unsolved when an expert in the field considers it unsolved or when several experts in the field disagree about a solution to a problem.
Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.
Extraction in chemistry is a separation process consisting of the separation of a substance from a matrix. The distribution of a solute between two phases is an equilibrium condition described by partition theory. This is based on exactly how the analyte moves from the initial solvent into the extracting solvent.
is an alkaline solution of potassium permanganate; used in organic chemistry as a qualitative test for the presence of unsaturation, such as double bonds; N-Bromosuccinimide: used in radical substitution and electrophilic addition reactions in organic chemistry. Also acts as a mild oxidizer to oxidize benzylic or allylic alcohols.
In Queensland, Year 11 students are the youngest in the country, as they usually enter at age fifteen. In New South Wales, Year 11 is the shortest year as it only lasts three whole terms. Students commence Year 12 in Term 4 instead of completing a fourth term of Year 11. Year 11 is followed by Year 12, the final year of high school.
A Polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings.Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, [1] or when biomass burns at lower temperatures as in forest fires.
The standard for fish for human consumption is less than 1 mg/kg, but many tested samples were more than five times that amount. [140] Chromium, especially hexavalent chromium, is highly toxic to fish because it is easily absorbed across the gills, readily enters blood circulation, crosses cell membranes and bioconcentrates up the food chain.