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  2. Law of definite proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_definite_proportions

    The law of definite proportion was given by Joseph Proust in 1797. [2]I shall conclude by deducing from these experiments the principle I have established at the commencement of this memoir, viz. that iron like many other metals is subject to the law of nature which presides at every true combination, that is to say, that it unites with two constant proportions of oxygen.

  3. National Council of Educational Research and Training

    en.wikipedia.org/wiki/National_Council_of...

    The program was renamed to National Talent Search Scheme with the NTSE examination now being conducted for classes X, XI, and XII. Currently, the NTSE exam is conducted only for 10th class students in India in two phases with subjects relating to Mental Ability Test and Scholastic Aptitude Test (SAT) for 100 marks each. [6] [7]

  4. Mass fraction (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Mass_fraction_(chemistry)

    Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...

  5. Metallurgy - Wikipedia

    en.wikipedia.org/wiki/Metallurgy

    Metallurgy derives from the Ancient Greek μεταλλουργός, metallourgós, "worker in metal", from μέταλλον, métallon, "mine, metal" + ἔργον, érgon, "work" The word was originally an alchemist's term for the extraction of metals from minerals, the ending -urgy signifying a process, especially manufacturing: it was discussed in this sense in the 1797 Encyclopædia ...

  6. Biuret test - Wikipedia

    en.wikipedia.org/wiki/Biuret_test

    In chemistry, the biuret test (IPA: / ˌ b aɪ j ə ˈ r ɛ t /, / ˈ b aɪ j ə ˌ r ɛ t / [1]), also known as Piotrowski's test, is a chemical test used for detecting the presence of at least two peptide bonds in a molecule. In the presence of peptides, a copper(II) ion forms mauve-colored coordination complexes in an alkaline solution.

  7. Segregation (materials science) - Wikipedia

    en.wikipedia.org/.../Segregation_(Materials_Science)

    In materials science, segregation is the enrichment of atoms, ions, or molecules at a microscopic region in a materials system. While the terms segregation and adsorption are essentially synonymous, in practice, segregation is often used to describe the partitioning of molecular constituents to defects from solid solutions, [1] whereas adsorption is generally used to describe such partitioning ...

  8. Training, validation, and test data sets - Wikipedia

    en.wikipedia.org/wiki/Training,_validation,_and...

    A training data set is a data set of examples used during the learning process and is used to fit the parameters (e.g., weights) of, for example, a classifier. [9] [10]For classification tasks, a supervised learning algorithm looks at the training data set to determine, or learn, the optimal combinations of variables that will generate a good predictive model. [11]

  9. Aqueous solution - Wikipedia

    en.wikipedia.org/wiki/Aqueous_solution

    An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula . For example, a solution of table salt , also known as sodium chloride (NaCl), in water would be represented as Na + (aq) + Cl − (aq) .