Question

mass fraction defination
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Answer 1

The atomic masses of most elements are fractional because they exist as a mixture of isotopes of different masses. Most elements occur as a mixture of isotopes of different masses. The fractional atomic masses arise because of this mixture. Avg. mass = total massof all atoms/number of atoms.

Answer 2

In chemistry,the mass friction of a substance within a mixture is the ratio of the mass of that substance to the total mass of the mixture.