Question

Nitrogen(N) is made up of 99.632% 14N and 0.368% 15N.

The atomic mass of 14N is 14.003 amu. The atomic mass of 15N is 15.000 amu.

What is the average atomic mass of nitrogen?

Responses

14.0 amu
14.0 lowercase a m u

14.006 amu
14.006 lowercase a m u

15.00 amu
15.00 lowercase a m u

15.50 amu
15.50 lowercase a m u

Answer 1

Average mass = (0.99632)(14.003) + (0.00368)(15.000)
= 13.951469 + 0.055200
≈ 14.006669 amu

Closest choice: 14.006 amu (14.006 lowercase a m u).