A ballon has 5.0 g mole of helium at 7°C. Calculate the number of atoms of helium in the balloon the total internal energy of the system.

Question

A ballon has 5.0 g mole of helium at 7°C. Calculate

(a) the number of atoms of helium in the balloon

(b) the total internal energy of the system.

Answer 1

μ = 5.0

T = 280K

No of atoms = μN_A = 5.0 x 6.02 x 10²³ 

= 30 × 1023

Average kinetic energy per molecule = (3/2)kT

Total internal energy = (3/2)kT x N

 = (3/2) x 30 x 10²³ x 1.38 x 10^-23 x 280

 = 1.74 x 10⁴ J