Final answer:
The atomic mass of Inertron is calculated by multiplying the abundance of each isotope by its respective mass and summing the results, yielding an atomic mass of 37.630 amu, which is closest to choice D. 38.25 amu.
Step-by-step explanation:
To find the atomic mass of the hypothetical element Inertron with its two isotopes, one weighing 37.05 amu with a natural abundance of 74%, and the other weighing 39.05 amu with a natural abundance of 26%, we use the formula for calculating average atomic mass:
Atomic mass = (% of isotope 1 × mass of isotope 1) + (% of isotope 2 × mass of isotope 2).
To apply this formula, we must first convert the percentage abundances into decimal form:
- % of isotope 1 = 74% = 0.74
- % of isotope 2 = 26% = 0.26
Plugging the values into the formula, we get:
Atomic mass = (0.74 × 37.05 amu) + (0.26 × 39.05 amu)
Atomic mass = 27.477 amu + 10.153 amu
Atomic mass = 37.630 amu
Therefore, the closest answer choice to the calculated atomic mass is D.38.25 amu.