Question

There are three naturally occurring isotopes
of the hypothetical element hilarium 41Hi,
42Hi, and 44Hi. The percentages of these
isotopes are the following:
Hilarium Natural
Isotopes Abundance
41Hi 28.3%
42Hi 42.9%
44Hi 28.8%
You can assume that the atomic masses are
exactly equal to the mass number. Calculate
the weight of “naturally” occurring hilarium
and report it as you would for any other naturally occurring element.
Answer in units of g/mol. Your answer
must be within ± 0.005%

Answer 1

Explanation:

$^{41}\text{Hi}: 41.000\:\text{g/mol}×0.283 = 11.603\:\text{g/mol}$

$^{42}\text{Hi}: 42.000\:\text{g/mol}×0.429 = 18.018\:\text{g/mol}$

$^{44}\text{Hi}: 44.000\:\text{g/mol}×0.288 = 12.672\:\text{g/mol}$

Adding all the weighted values on the right hand side, we get

$\text{Hi}: 42.293\:\text{g/mol}$