What mass of magnesium oxide is formed when 6 g of magnesium reacts with oxygen?

Approx. a $10 \cdot g$ mass is formed.
$M g \left(s\right) + \frac{1}{2} {O}_{2} \left(g\right) \rightarrow M g O \left(s\right)$
$\text{Moles of metal}$ $=$ $\frac{6.0 \cdot g}{24.31 \cdot g \cdot m o {l}^{-} 1}$ $=$ $0.247 \cdot m o l$.
And thus there are $0.247 \cdot m o l \times 40.3 \cdot g \cdot m o {l}^{-} 1$ $\text{magnesium oxide}$ $\cong$ $10 \cdot g$