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The discovery of phenolphthalein's laxative effect was due to an attempt by the Hungarian government to label [clarification needed] genuine local white wine with the substance in 1900. Phenolphthalein did not change the taste of the wine and would change color when a base is added, making it a good label in principle.
Phenolphthalein can be synthesized by the condensation of phthalic anhydride with two equivalents of phenol under acidic conditions (hence the name). It was discovered in 1871 by Adolf von Baeyer. [8] [9] [10] Synthesis of phenolphthalein [11]
[169] [170] Hafnium was the last stable element to be discovered (noting however the difficulties regarding the discovery of rhenium). 43 Technetium: 1937 C. Perrier and E. Segrè: 1937 C. Perrier & E. Segrè The two discovered a new element in a molybdenum sample that was used in a cyclotron, the first element to be discovered by synthesis. It ...
Brand kept his discovery secret, as alchemists of the time did, and worked with the phosphorus trying unsuccessfully to use it to produce gold. His recipe was: [5] Let urine stand for days until it gives off a pungent smell. [4] (This step was not necessary, as later scientists discovered that fresh urine yielded the same amount of phosphorus). [6]
This category identifies chemists who have discovered one or more chemical elements. See also. Discoveries of the chemical elements; Periodic table Subcategories ...
Newlands arranged all of the known elements, starting with hydrogen and ending with thorium (atomic weight 232), into eight groups of seven, which he likened to octaves of music. [6] [7] In Newlands' table, the elements were ordered by the atomic weights that were known at the time and were numbered sequentially to show their order.
Friedrich Wilhelm Ostwald (German: [ˈvɪlhɛlm ˈɔstˌvalt] ⓘ; 2 September [O.S. 21 August] 1853 – 4 April 1932) was a German chemist and philosopher.Ostwald is credited with being one of the founders of the field of physical chemistry, with Jacobus Henricus van 't Hoff, Walther Nernst and Svante Arrhenius. [1]
Carl Wilhelm Scheele (German:, Swedish: [ˈɧêːlɛ]; 9 December 1742 – 21 May 1786 [2]) was a German Swedish [3] pharmaceutical chemist.. Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, nitrogen, and chlorine, among others.