Dumas Method Quick Trick — Find %N in Organic Compound (50 mL N₂) 🔬
❓ Question In Dumas' method , 292 mg of an organic compound released 50.0 mL of nitrogen gas (N₂) at 300 K and 715 mm Hg total pressure. Aqueous tension at 300 K = 15 mm Hg . Find the percentage composition of nitrogen (N) in the organic compound. (Nearest integer) 🖼️ Question Image ✍️ Short Solution Step 1 — Correct the gas pressure for water vapor Total pressure above the collected gas includes water vapor. The partial pressure of dry N₂ is: P N 2 = P total − P H 2 O = 715 − 15 = 700 mm Hg . Step 2 — Use ideal gas law to find moles of N₂ Use P V = n R T. Convert volume to litres: V = 50.0 mL = 0.0500 L V = 50.0\ \text{mL} = 0.0500\ \text{L} . Use gas constant in mmHg·L units: R = 62.3637 L \ mmHg \ mol − 1 \ K − 1 . So n N 2 = P N 2 V R T = 700 × 0.0500 62.3637 × 300 . Calculate numerator: 700 × 0.0500 = 35.0 700\times0.0500 = 35.0 . Denominator: 62.3637 × 300 = 18709.11 62.3637\times300 = 18709.11 . Thus n N 2 = 35...