Response:
U = 12,205.5 J
Clarification:
To determine the internal energy of an ideal gas, use the following equation:
(1)
U: internal energy
R: ideal gas constant = 8.135 J(mol.K)
n: number of moles = 10 mol
T: the temperature of the gas = 100K
Substituting the parameter values into equation (1):

The overall internal energy for 10 moles of Oxygen at 100K is 12,205.5 J