Given an excess of nitrogen gas, how many grams of Li3N can be formed from 1.75 moles of Li? (Molar mass of Li3N = 34.83 g/mol)

• A. 20.3 g
• B. 10.2 g
• C. 34.8 g
• D. 5.83 g

Answer: (A)

Verified step by step guidance

1. Write the balanced chemical equation for the reaction between lithium (Li) and nitrogen gas (N\_2) to form lithium nitride (Li\_3N). The balanced equation is: \$6\ \mathrm{Li} + \mathrm{N}_2 \rightarrow 2\ \mathrm{Li}_3\mathrm{N}$.
2. Determine the mole ratio between lithium and lithium nitride from the balanced equation. From the equation, 6 moles of Li produce 2 moles of Li\_3N, so the mole ratio is \(\frac{2}{6} = \frac{1}{3}\) mole of Li\_3N per mole of Li.
3. Calculate the moles of Li\_3N formed from 1.75 moles of Li using the mole ratio: \(\text{moles of Li}_3\mathrm{N} = 1.75 \times \frac{1}{3}\).
4. Use the molar mass of Li\_3N (34.83 g/mol) to convert moles of Li\_3N to grams: \(\text{mass of Li}_3\mathrm{N} = \text{moles of Li}_3\mathrm{N} \times 34.83\ \mathrm{g/mol}\).
5. Perform the multiplication to find the mass of Li\_3N formed from 1.75 moles of Li.