One kilogram of a diatomic gas is at a pressure of  8×104Nm−2. The density of the gas  is  4kgm−3. What is the energy of the gas due to its thermal motion?

Thermal energy corresponds to internal energyAs per law of equipartition of energy,Energy per mole =  fRT2Hence energy of gas =  number  of  molesfRT2=nfRT2=fPV2=58×104Nm−214m32=5×104J