# How many moles are in 3.70 * 10^-1 g of boron?

1 mol of boron has a mass of $10.81$ $g$. To find the molar quantity divide the mass by the molar mass.
Molar quantity $=$ $\frac{3.70 \times {10}^{- 1} \cdot \cancel{g}}{10.81 \cdot \cancel{g} \cdot m o {l}^{-} 1}$ $=$ ?? mol. Note how this treatment is dimensionally consistent; I used $g$ and $g \cdot m o {l}^{-} 1$ units, and I get an answer in $m o l$ as required $\left({\left(m o {l}^{-} 1\right)}^{-} 1 = m o l\right)$.