Question

Element Z has 2 isotopes. A sample of element Z contains 19% Z234 and 81% Z236. What is the average atomic mass of the element Z?

Answer 1

Wt Avg of the two isotopes = 235.62 amu

Step-by-step explanation:

Given:

abundance

Isotope % fractional mass (amu) Wt. Avg. Contributions

Z234 19% 0.19 234 (0.19)(234) = 44.46 amu

Z236 81% 0.81 236 (0.81)(236) = 191.16 amu

Collective Wt. Avg. of all isotopes = ∑ Wt. Avg. Contributions

= 44.46 amu + 191.16 amu = 235.62 amu