Question

Equal masses of methane and oxygen are mixed in an empty
container at 25°C. The fraction of the total pressure exerted
by oxygen is
(a) 1/2 (b) 2/3 (c) 1/3 273/298 (d) 1/3.

Answer 1

Equal masses of methane and oxygen are mixed in an empty

container at 25°C. The fraction of the total pressure exerted

by oxygen is (d) 1/3

- Let the mass of methane and oxygen mixed together be 'm' gm and the total pressure exerted by the mixture be P

- molar mass of oxygen = 32 gm

- molar mass of methane = 16 gm

- mole fraction of oxygen = (m/32)/ {(m/32)+(m/16)}

                                          = 1/3

- Now, partial pressure exerted by oxygen = Pressure × Mole fraction

                                                           = P × 1/3 = P/3

- Thus, fraction of total pressure exerted by oxygen is 1/3

- So the correct answer is option (d)

Answer 2

Answer:

Equal masses of methane and oxygen are mixed in an empty

container at 25°C. The fraction of the total pressure exerted

by oxygen is (d) 1/3

- Let the mass of methane and oxygen mixed together be 'm' gm and the total pressure exerted by the mixture be P

- molar mass of oxygen = 32 gm

- molar mass of methane = 16 gm

- mole fraction of oxygen = (m/32)/ {(m/32)+(m/16)}

                                         = 1/3

- Now, partial pressure exerted by oxygen = Pressure × Mole fraction

                                                          = P × 1/3 = P/3

- Thus, fraction of total pressure exerted by oxygen is 1/3

- So the correct answer is option (d)