A gas cylinder contains 12 x 1024 molecules of oxygen gas

Mole Concept (10)

A gas cylinder contains 12 x 1024 molecules of oxygen gas:

If Avogadro's number is 6x1023; Calculate:

  1. the mass of oxygen present in the cylinder.
  2. the volume of oxygen at S.T.P. present in the cylinder. [O=16]

Answer

  1. 6x1023 molecules of O2 have a mass of 32g
    ∴ 12x1024 molecules of O2 have a mass of 32x12x1024/ 6x1023
    = 640g.                                                                                                                                                                                        
  2. No. of moles of O2 = 12 x 1024 / 6 x 1023 = 20
    ∴ Volume of O2 at S.T.P. = 20 x 22.4 = 448 l
    Hence volume of 640 g at s.t.p. = 22.4 x 640 / 32= 448l.

 

 

 

  • Exam Year: 2016