Question

mass of magnesium (g) 0.217
moles of magnesium (mol) blank box

Explanation:

Step1: Recall the molar mass of Mg

The molar mass of magnesium (Mg) is approximately $24.305\ \text{g/mol}$.

Step2: Use the formula $n = \frac{m}{M}$

Where $n$ is the number of moles, $m$ is the mass, and $M$ is the molar mass. Here, $m = 0.217\ \text{g}$ and $M = 24.305\ \text{g/mol}$. So we calculate $n=\frac{0.217\ \text{g}}{24.305\ \text{g/mol}}$.

Step3: Perform the division

$\frac{0.217}{24.305}\approx0.00893\ \text{mol}$ (rounded to appropriate significant figures).

Answer:

The moles of magnesium is approximately $0.00893\ \text{mol}$ (or depending on significant figures, could be adjusted, for example, if we consider three significant figures from 0.217, it's $8.93\times10^{-3}\ \text{mol}$).