Question

3. Calculate the atomic mass of oxygen if the three common isotopes of oxygen have masses

of 15.995 amu (99.759% abundance), 16.995 amu (0.037 % abundance), and 17.999 amu
(0.204 % abundance).

Answer 1

15.999 amu

Step-by-step explanation:

15.999 amu

Explanation:

From the question given above, the following data were:

Isotope A:

Mass of A 15.995 amu

Abundance (A%) = 99.759%

Isotope B:

Mass of B = 16.995 amu

Abundance (B%) = 0.037%

Isotope C:

Mass of C = 17.999 amu

Abundance (C%) = 0.204%

Atomic mass of Oxygen =.?

The atomic mass of oxygen can be calculated by using the following formula:

Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]

Atomic mass = [(15.995 × 99.759)/100] + [(16.995 × 0.037)/100] + [(17.999 × 0.204)/100]

Atomic mass = 15.956 + 0.006 + 0.037

Atomic mass = 15.999 amu

Therefore, the atomic mass of oxygen is 15.999 amu