1 Research products, page 1 of 1

  • Publication . Article . Other literature type . 2021
    Open Access English
    Nenad Raos;
    Publisher: Croatian Society of Chemical Engineers
    Country: Croatia

    There are two basic understandings of relative atomic mass. The first (“atomic weight”) stems from the law of constant and multiple mass proportions and has no reference to the size and the absolute mass of atoms. “Atomic weights” were defined and measured in the 19th Century, and at that time atoms and molecules were just hypothetical particles. However, in the 20th Century, it became possible to measure the number and mass of atoms, and relative atomic mass was defined in reference to the mass and number of atoms, i.e. Avogadro constant and mole. This also resulted in the change of reference unit, Ar(H) = 1 or Ar(O) = 16, for Ar(12C) = 12, and the way of teaching of stoichiometry (calculations via nA instead of using proportionality principle). This article also describes the history of “atomic weight” determination by gravimetric analysis, especially the work of J. J. Berzelius and J. S. Stas. This work is licensed under a Creative Commons Attribution 4.0 International License. Pojam relativne atomske mase pojavljuje se u dva značenja: prvo proizlazi iz zakona stalnih masenih omjera („atomska težina“), a drugo, novije, iz definicije mola, kao Avogadrova broja atoma (čestica). U članku je opisana kako povijest određivanja „atomske težine“ (Dalton, Berzelius, Stas) tako i povijest njezina definiranja (prema vodiku, kisku ili nuklidu 12C). Dva značenja relativne atomske mase utjecala su i na način rješavanja stehiometrijskih zadataka. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.

Send a message
How can we help?
We usually respond in a few hours.