In Dumas' method of estimation of nitrogen, 0.1840 g of an organic compound gave 30 mL of nitrogen collected at 287 K and 758 mm of Hg pressure. The percentage composition of nitrogen in the compound

Question

In Dumas' method of estimation of nitrogen, 0.1840 g of an organic compound gave 30 mL of nitrogen collected at 287 K and 758 mm of Hg pressure. The percentage composition of nitrogen in the compound is . (Round off to the nearest integer).

[Given: Aqueous tension at 287 K = 14 mm of Hg]

Canvas Classes · Accepted Answer

Step 1: Correct for Aqueous Tension

The  is collected over KOH solution at 287 K. Vapour pressure of water at 287 K = 14 mm Hg.

Converting to atm:

Step 2: Calculate Moles of N₂ Using Ideal Gas Law

Given:
- 
- 
- n{N2} = \frac{PV}{RT} = \frac{0.9789 	imes 0.030}{0.0821 	imes 287} = \frac{0.029368}{23.562} = 1.2464 	imes 10^{-3} 	ext{ mol}\ce{N2}m{N2} = 1.2464 	imes 10^{-3} 	imes 28 = 0.034898 	ext{ g}mN = m{N2}\ce{N2}\%N = \frac{0.034898}{0.1840} 	imes 100 = 18.97\% \approx \mathbf

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