What is the atomic mass of $\mathrm{Fe}$ ? Given abundance of ${ }^{54} \mathrm{Fe}=10 \%$ $ \begin{aligned}…
What is the atomic mass of $\mathrm{Fe}$ ?
Given abundance of ${ }^{54} \mathrm{Fe}=10 \%$
$
\begin{aligned}
& { }^{56} \mathrm{Fe}=85 \% \\
& { }^{57} \mathrm{Fe}=5 \%
\end{aligned}
$
55.65
55.75
55.85
55.95
Solution
Average atomic mass of $\mathrm{Fe}=54 \times 0.1+56 \times 0.85+$ $57 \times 0.05=55.85$