A1.2-mol sample of hydrogen gas has a temperature of 21 ∘c.

Missing question (found on internet):
What is the total translational kinetic energy of all the gas molecules in the sample? Express your answer using two significant figures.

Solution:
The average translational kinetic energy of the molecules in a gas is given by:
where
kB is the Boltzmann's constant
T is the absolute temperature of the gas.
In our problem, the absolute temperature is 

therefore the average translational kinetic energy of the molecules is


In this problem, we have 1.2 mol of this gas, and since one mole of ideal gas contains a number of molecules equal to Avogadro number, the total number of molecules in our gas is


So the total translational kinetic energy of all molecules of the gas is

10 is the . . .