Question

If the atomic mass unit ‘u’ were defined to be `1/5 "th"` of the mass of an atom of C-12, what would be the atomic weight of nitrogen in amu or ‘u’ in this state? Atomic weight of N on the conventional scale is 14.

Options

• 6.77 u

• 5.834 u

• 14 u

• 23 u

Answer 1

5.834 u

Explanation:

Weight = `"absolute at. wt."/(1 "amu")`

14 = `"absolute at. wt."/(1/12 xx 12/"N"_"A" "g")` ...(1)

x = `"absolute at. wt."/(1/5 xx 12/"N"_"A" "g")` ...(2)

x = 5.83 amu