of a sample of is burnt in excess oxygen. of is obtained. The percentage purity of in the sample is: — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

$Mg + 1/2 O_2 \rightarrow MgO$. <br>$\text{Moles } MgO = 3 / 40 = 0.075$. <br>$\text{Mass of pure Mg} = 0.075 \times 24 = 1.8 \text{ g}$. <br>$\% \text{ purity} = (1.8 / 2) \times 100 = 90\%$.