Q. Oxygen gas generated by the decomposition of potassium chlorate is collected. The volume of oxygen collected at $24℃$ and atmospheric pressure of 760 mm Hg is 128 mL. Calculated the mass of oxygen gas obtained. The pressure of the water vapour at $24℃$ is 22.4 mm Hg
A) 0.123 g
B) 0.163 g
C) 0.352 g
D) 1.526 g
Explanation
(b)
From the total pressure and the vapour pressure of water, we can calculate the partial pressure of $O_{2}$
${p_{O}}_{2} = p_{T} - p_{H_{2}O} = 760 - 22.4 = 737.6\$mm Hg
From the ideal gas equation we write
$m = \frac{pVM}{RT}$
$= \frac{0.974 \times 0.128 \times 32.0}{0.0821 \times 297} = 0.163\ g$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.