AP EAPCET 07-Jul-2022 Shift 2 Paper

Translational kinetic energy of a gas volume is
U=

f

2

RT
Where, f= degrees of freedom of gas molecules.
- Now, f=3 for He or Ar monoatomic and f=5 for H2 or N2 Diatomic.
Hence, for 3 moles of He, 1 mole Ar, 5 moles of N2 and 3 moles of H2.
U=3×

3

2

RT+1×

3

2

RT+5×

5

2

RT+3×

5

2

RT
=(

9

2

+

3

2

+

25

2

+

15

2

)RT
=

52

2

RT=26RT