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  2. Chinese Chemistry Olympiad - Wikipedia

    en.wikipedia.org/wiki/Chinese_Chemistry_Olympiad

    Chinese Chemistry Olympiad (Chinese: 中国化学奥林匹克竞赛) is an annual academic competition held by Chinese Chemical Society. [1] CAS changed its official Chinese name in February 2014, though its English translation remains the same. [2] [3] The first CChO was held in 1984, 16 years after IChO. The event has been held every year ...

  3. Phosphor - Wikipedia

    en.wikipedia.org/wiki/Phosphor

    P1, GJ Zn 2 SiO 4:Mn Green 525 nm 40 nm [34] 1-100ms CRT, Lamp Oscilloscopes and monochrome monitors: P2 ZnS:Cu(Ag)(B*) Blue-Green 543 nm – Long CRT Oscilloscopes P3 Zn 8:BeSi 5 O 19:Mn Yellow 602 nm – Medium/13 ms CRT Amber monochrome monitors P4 ZnS:Ag+(Zn,Cd)S:Ag White 565,540 nm – Short CRT Black and white TV CRTs and display tubes.

  4. Phosphorus tribromide - Wikipedia

    en.wikipedia.org/wiki/Phosphorus_tribromide

    The main use for phosphorus tribromide is for conversion of primary or secondary alcohols to alkyl bromides, [9] as described above.PBr 3 usually gives higher yields than hydrobromic acid, and it avoids problems of carbocation rearrangement- for example even neopentyl bromide can be made from the alcohol in 60% yield.

  5. GHS precautionary statements - Wikipedia

    en.wikipedia.org/wiki/GHS_precautionary_statements

    Precautionary statements form part of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). [1] They are intended to form a set of standardized phrases giving advice about the correct handling of chemical substances and mixtures, which can be translated into different languages.

  6. Reaction quotient - Wikipedia

    en.wikipedia.org/wiki/Reaction_quotient

    In chemical thermodynamics, the reaction quotient (Q r or just Q) [1] is a dimensionless quantity that provides a measurement of the relative amounts of products and reactants present in a reaction mixture for a reaction with well-defined overall stoichiometry at a particular point in time.

  7. Crystallographic point group - Wikipedia

    en.wikipedia.org/wiki/Crystallographic_point_group

    In Schoenflies notation, point groups are denoted by a letter symbol with a subscript. The symbols used in crystallography mean the following: C n (for cyclic) indicates that the group has an n-fold rotation axis.

  8. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    As the concentration increases the colour becomes a more vibrant yellow, then orange, with the final 10,000 ppm a deep red colour. In science and engineering , the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities , e.g. mole fraction or mass fraction .

  9. Ideal gas law - Wikipedia

    en.wikipedia.org/wiki/Ideal_gas_law

    Isotherms of an ideal gas for different temperatures. The curved lines are rectangular hyperbolae of the form y = a/x. They represent the relationship between pressure (on the vertical axis) and volume (on the horizontal axis) for an ideal gas at different temperatures: lines that are farther away from the origin (that is, lines that are nearer to the top right-hand corner of the diagram ...