Chapter 15, Problem 8RAT

To determine

The correct option for the statement “If, hypothetically, $80.0\%$ of the atoms of an element had an atomic mass of $80.00$, and the other $20.0\%$ with an atomic mass of $82.00$, what is the approximate atomic mass of the element?”.

Answer to Problem 8RAT

The correct option for the statement “If, hypothetically, $80.0\%$ of the atoms of an element had an atomic mass of $80.00$, and the other $20.0\%$ with an atomic mass of $82.00$, what is the approximate atomic mass of the element?” is option (a).

Explanation of Solution

In a given element $80.0\%$ of the atoms of an element had an atomic mass of 80.00, and the other $20.0\%$ with an atomic mass of 82.00.

Write the steps to calculate the approximate atomic mass of an element.

$\begin{array}{l}0.80\times 80=64\text{amu}\\ 0.20\times 82=16.4\text{amu}\end{array}$

Average mass of an element is the sum of the individual atomic mass of atoms present in molecules.

Write the steps to calculate the approximate atomic mass of an element.

$\begin{array}{c}\text{Atomic}\text{mass}=64+16.4\\ =80.4\text{amu}\end{array}$

Conclusion:

Therefore, the correct option for the statement “If, hypothetically, $80.0\%$ of the atoms of an element had an atomic mass of $80.00$, and the other $20.0\%$ with an atomic mass of $82.00$, what is the approximate atomic mass of the element?”is option (a).