In the estimation of nitrogen using the Dumas method, 0.3 text g of an organic compound yielded 50 text mL of nitrogen gas collected at 300 text K and 715 text mm Hg pressure. Determine the percentage of nitrogen in the compound. (Aqueous tension at 300 text K = 15 text mm Hg )

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EEJ MAIN Chemistry QUESTION #7193

Question 1

In the estimation of nitrogen using the Dumas method, $0.3 \text{ g}$ of an organic compound yielded $50 \text{ mL}$ of nitrogen gas collected at $300 \text{ K}$ and $715 \text{ mm Hg}$ pressure. Determine the percentage of nitrogen in the compound. (Aqueous tension at $300 \text{ K} = 15 \text{ mm Hg}$)

15.46%
17.46%✔️
16.46%
18.46%

Correct Answer Explanation

First, calculate the volume of nitrogen at STP ($P_1V_1/T_1 = P_2V_2/T_2$):

$P_1 = 715 - 15 = 700 \text{ mm Hg}$ [cite: 3, 53]
$V_1 = 50 \text{ mL}$, $T_1 = 300 \text{ K}$ [cite: 18]
$V_{STP} = \frac{700 \times 50 \times 273}{300 \times 760} \approx 41.9 \text{ mL}$ [cite: 19]
Mass of $N_2 = \frac{28 \times 41.9}{22400} \approx 0.0524 \text{ g}$ [cite: 54]
$\% \text{ Nitrogen} = \frac{0.0524}{0.3} \times 100 \approx 17.46\%$ [cite: 56]

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