3). 150°C and 100 kPa
Gases behave ideally at high temperatures and low pressures (less intermolecular forces)
Temperature is a statistical quantity. The formal definition<span> is T = dU/dS, the change in internal </span>energy<span> with respect to entropy holding volume and particle number constant. A practical </span>definition<span> comes from the fact that the atoms, molecules, or whatever particles in a system have an </span>average kinetic energy<span>.</span>