In Dumas' method for estimation of nitrogen 1 g of an organic compound gave 150 mL of nitrogen collected at 300 K temperature and 900 mm Hg pressure. The percentage composition of nitrogen in the comp

Question

In Dumas' method for estimation of nitrogen 1 g of an organic compound gave 150 mL of nitrogen collected at 300 K temperature and 900 mm Hg pressure. The percentage composition of nitrogen in the compound is  % (nearest integer). (Aqueous tension at 300 K = 15 mmHg)

Canvas Classes · Accepted Answer

Step 1: Correct for Aqueous Tension

The  gas is collected over water at 300 K:

Step 2: Convert Volume to STP

Given:  mL,  K,  mm Hg

STP:  K,  mm Hg

Step 3: Apply Dumas Formula

Where  = mass of compound = 1 g

Step 4: Conclusion

%N = 20 (nearest integer)

Key Points to Remember:
- Three-step Dumas calculation: (1) correct for aqueous tension, (2) convert to STP, (3) apply formula
- Formula: 
- High pressure (900 mmHg) means more moles of gas in the same volume → higher %N
- Aqueous

More questions from Practical Organic Chemistry