Use Avogadrs's number to show that the a...

Use Avogadrs's number to show that the atomic mass unit is `1` u `=1.66 xx 10^(-27) kg`.

Text Solution

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Mass of Avogardo number of atoms of `.^(12)C` is exactly `12 g`. Avogadro's number, `N_(A)` has the value `6.02 xx 10^(23) "atoms" mol^(-1)` ltbtgt Thus, the mass of one carbon atom is
`(0.0012 kg)/(6.02 xx 10^(23) "atom") =1.99 xx 10^(-26)kg`
Since one ctom of `.^(12)C` is defined to have a mass of `12 u`, we find that
` 1u =(1.99xx 10^(26) kg)/(12) =1.66xx10^(-27) kg`.

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