In Dumas method one gram of carbon compound gives 50 mL of N 2 at 300 K and 740 mm Hg pressure. If the aqueous tension at 300 K is 15 mm Hg, what is the percentage of nitrogen in it?

Question

In Dumas method one gram of carbon compound gives 50 mL of N 2 at 300 K and 740 mm Hg pressure. If the aqueous tension at 300 K is 15 mm Hg, what is the percentage of nitrogen in it? (A) 42 (B) 10.84 (C) 21.68 (D) 2.71

Tardigrade Admin · Accepted Answer

Given, p=740 mm of Hg dry gas pressure p1=740-15=725 mm Hg V1=50 mL T1=300 K , p2=760 mm Hg , T2=273 K From the combine gas equation, (p1 V1/T1)=(p2 V2/T2) ⇒ (725 × 50/300)=(760 × V2/273) V2=(725 × 50 × 273/300 × 760)=43.4 mL 22.4 L of N 2 longrightarrow 28 g of N 2 at STP (22400 mL) 4.3 .4 L of N 2 → (28 × 43.4 /22400) =5.4 × 10-2 g of N2 % mass of N 2 =( text Mass of N 2/ text Mass of substance ) × 100 =(5.4 × 10-2/ 1 ) × 100 =5.4 %

Q. In Dumas method one gram of carbon compound gives 50mL of N2​ at 300K and 740mmHg pressure. If the aqueous tension at 300K is 15mmHg, what is the percentage of nitrogen in it?

42

10.84

21.68

2.71

Q. In Dumas method one gram of carbon compound gives $50 m L$ of $N_{2}$ at $300 K$ and $740 mm H g$ pressure. If the aqueous tension at $300 K$ is $15 mm H g$ , what is the percentage of nitrogen in it?