Element Z has 2 natural isotopes. One isotope has a mass of 15.0amu and has a relative abundance of 30%. The other isotope has a mass of 16.0amu and has a relative abundance of 70%. Estimate the average atomic mass for this element to one decimal place.

The answer to your question is 15.7 amu

Explanation:

Abundance Mass

Isotope 1 30% 15

Isotope 2 70% 16

Average atomic mass = (Abundance isotope 1 x abundance) +

(Abundance isotope 2 x abundance)

Substitution

Average atomic mass = (0.30 x 15) + (0.70 x 16)

Simplify

Average atomic mass = 4.5 + 11.2

Result

Average atomic mass = 15.7 amu