1)

 A container of fixed volume has a mixture  of one mole of hydrogen  and one mole  of helium  in equilibrium at temperature  T. Assuming the gases are ideal, the correct statement is/are


A) The average energy per mole of the gas mixture is 2RT

B) The ratio of speed of sound in the gas mixture to that in helium gas is 65

C) The ratio of the rms speed of helium atoms to that of hydrogen molecules is 12

D) The ratio of the rms speed of helum atoms to that of hydrogen molecules is 12

Answer:

Option A,B,D

Explanation:

(a)  Total  Internal energy

          U=f12nRT+f22nRT

                    (Uave)permole=U2n

  =     14[5RT+3RT]=2RT

  (b)                    γmix=n1Cp1+n2Cp2n2Cv1+n2Cv2

      =(1)7R2+(1)5R2(1)5R2+(1)3R2=32

              Mmix=n1M1+n2M2n1+n2

                   M1+M22=2+42=3

 speed of sound          V=γRTM

                        VYM

                 VmixVHe=γmixγHe×MHeMmix

                   =    VmixVHe=3/25/3×43=65

 (d)        Vrms=3RTMVrms1M

                    VHeVH=MHMHe=24=12