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प्रश्न
Define the term Relative molecular mass. State why indirect methods are utilised to determine the absolute mass of an atom. Explain in brief the indirect method used.
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उत्तर
Relative molecular mass [RMM] of an element/compound : “Is the number of times one molecule of the substance is heavier than 1/12 the mass of an atom of carbon [C12].
RAM = `"Mass of one atom of the element"/("Mass of one atom of carbon"["C"^12])`
OR
“Mass of one molecule as compared with the 1/12 mass of an atom of carbon[C12]”
RMM = `("Mass of one molecule of the substance")/((1/2) "Mass of one atom of carbon"["C"^12])`
To determine the absolute mass of an atom indirect methods are utilised as Atom are extremely small and very light.
An isotope of carbon C12 [carbon -12 atom] has been assigned an atomic mass of exactly 12 atomic mass units] is used.
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