Question

The average translational energy and rms speed of molecules in a sample of oxygen gas at 300 K are 6.21 x 10^-21 J and 484 ms^-1 respectively. The corresponding values at 600 K will be

(1) 12.42 x 10^-21 J, 968 ms^-1

(2) 8.78 x 10^-21 J, 984 ms^-1

(3) 6.21 x 10^-21 J, 968 ms^-1

(4) 12.42 x 10^-21 J, 684 ms^-1

Answer 1

(4) 12.42 x 10^-21 J, 684 ms^-1

We know the average translational energy is directly proportional to the temperature therefore 

Energy at 600 K = 2 x Energy at 300 K = 12.42 x 10^-21 J

The r.m.s speed v_rms is directly to proportional to √T ; therefore