# How many moles of iron in a 50*lb mass of iron?

Nov 27, 2016

$a .$ $\text{Formula mass}$ $=$ $\left(2 \times 55.85 + 3 \times 15.999\right) \cdot g \cdot m o {l}^{-} 1$.
$b .$ If you have a $50 \cdot l b$ mass, AND $1 \cdot l b \equiv 454 \cdot g$ (I don't know, I don't use these units, especially as the States has its own special variety), then..........
"Mass of iron in grams"-=50*cancel(lb)xx454*g*cancel(lb^-1)=??lbs
$\text{Moles of iron}$ $=$ $\frac{50 \cdot l b \times 454 \cdot g \cdot l {b}^{-} 1}{\left(2 \times 55.85 + 3 \times 15.999\right) \cdot g \cdot m o {l}^{-} 1} = 142 \cdot m o l$.