Question

One half mole each of nitrogen, oxygen and carbon dioxide are mixed in enclosure of volume 5 litres and temperature 27°C. The pressure exerted by mixture is

(R = 8.31 J mol–1 K–1)

• A. 7.8 × 105 N m–2
• B. 5 × 105 N m–2
• C. 6 × 105 N m–2
• D. 3 × 105 N m–2

Answer 1

Answer: (A)

7.8 × 105 N m–2

Answer 2

Using, Dalton’s law of partial pressures.

$P = P_{1} + P_{2} + P_{3} = \frac{nRT}{V} + \frac{nRT}{V} + \frac{nRT}{V}$

$= \frac{3nRT}{V}$ …. (i)

Here, $n = \frac{1}{2},T = 27{^\circ}C = 27 + 273 = 30K$

$V = 5 \times 10^{- 3}cc.$

$\therefore P = \frac{3 \times 8.31 \times 300}{2 \times 5 \times 10^{- 3}}$

$P = 7.48 \times 10^{5}Nm^{- 2}$