Oxygen occurs in nature as a mixture of isotopes 16O, 17O and 18O having atomic masses of 15.995 u, 16.999 u and 17.999 u and relative abundance of 99.763 %, 0.037 % and 0.200 % respectively. What is the average atomic mass of oxygen?

Question

Oxygen occurs in nature as a mixture of isotopes 16O, 17O and 18O having atomic masses of 15.995 u, 16.999 u and 17.999 u and relative abundance of 99.763 %, 0.037 % and 0.200 % respectively. What is the average atomic mass of oxygen? (A) 15.999 u (B) 16.999 u (C) 17.999 u (D) 18.999 u

Tardigrade Admin · Accepted Answer

Average atomic mass of oxygen =((99.763×15.995)+(0.037×16.999)+(0.200×17.999)/100) = 15.999 u

Q. Oxygen occurs in nature as a mixture of isotopes $^{16} O,^{17} O$ and $^{18} O$ having atomic masses of $15.995 u, 16.999 u$ and $17.999 u$ and relative abundance of $99.763%, 0.037%$ and $0.200%$ respectively. What is the average atomic mass of oxygen?

$15.999 u$

$16.999 u$

$17.999 u$

$18.999 u$

Average atomic mass of oxygen
$= \frac{( 99.763 \times 15.995 ) + ( 0.037 \times 16.999 ) + ( 0.200 \times 17.999 )}{100}$
$= 15.999 u$

Q. Oxygen occurs in nature as a mixture of isotopes 16O,17O and 18O having atomic masses of 15.995u,16.999u and 17.999u and relative abundance of 99.763%,0.037% and 0.200% respectively. What is the average atomic mass of oxygen?

15.999u

16.999u

17.999u

18.999u