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also, explain Atomic, Molecular and Molar Masses

7 years ago


Answers : (1)



    Dalton gave the idea of atomic mass in relative terms, that is, the average mass of one atom relative to the average ass of the other. The relative atomic masses were referred to as the atomic weights. It was found that 1.00 g of hydrogen combines with 8.0 g of oxygen to form water. In order to find out atomic mass of oxygen (relative to hydrogen) we need to know the relative numbers of hydrogen and oxygen atoms in water. However during Dalton’s time it was not known how many hydrogen and oxygen atoms are present in a water molecule. Now we know that a water molecule has two hydrogen and one oxygen atom.

    Thus, the atomic mass of oxygen relative to hydrogen is 16.

    Dalton’s hydrogen bases scale was eventually replaced by a scale based on oxygen, as it was considered more reactive forming a large number of compounds. For a universally accepted atomic mass unit in 1961, carbon-12 isotope was selected as standard. Today this scale depends on measurements of atomic mass by a mass spectrometer.

7 years ago

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