Question

7.72-g sample of magnesium reacts with the excess of nitrogen gas.

what is the mass of nitrogen consumed in grams

3 Mg(s) + N2(g) → Mg3N2(s)

Answer 1

2.97 g

Explanation:

First convert mass to moles.

7.72 g Mg × (1 mol Mg / 24.3 g Mg) = 0.318 mol Mg

Use stoichiometry to find moles of nitrogen.

0.318 mol Mg × (1 mol N₂ / 3 mol Mg) = 0.106 mol N₂

Convert moles to mass:

0.106 mol N₂ × (28.0 g N₂ / mol N₂) = 2.97 g N₂