Calculate the internal energy of `1 g` of oxygen STP.

Explanation

Oxygen is a diatomic gas. The average energy
per molecule is, therefore, `5/2 kT`and the average energy
per mole is 5/2RT. As the molecular weight of oxygen has
`n= 1g / 32 g mol^(-1) = 1/ 32mol.
The temperature of oxygen is 273 K. Thus, the internal energy is
U `=n (5/2 RT)`
`=( 1 /32 mol) (5/2) (8.31 J K^(-1) mol^(-1) (273 K )
177 J`.