A box contains about 5.64 x 1021 hydrogen

atoms at room temperature 21°C.

Find the thermal energy of these atoms.

Answer in units of J.

Given that,

The temperature of atom is 21°C

θ = 21 + 273 = 294K.

Then, from kinetic theory,

The kinetic energy of individual elements is

K. E = 2kT/3

k is Boltzmann constant

k = 1.38 * 10^-23 J/K•particle

Then,

K. E = 2 * 1.38 * 10^-23 * 294 / 3

K. E = 2.7048 * 10^-21 J/particle

Each particle of hydrogen is 5.64 * 10²¹ particle

Total K. E = 2.7048 * 10^-21 * 5.64 * 10²¹

Total K. E = 15.26 J