Final answer:
The kinetic molecular theory is less applicable for real gases under conditions of high pressure and low temperatures, due to increased intermolecular attraction and decreased particle motion.
Step-by-step explanation:
The two conditions that can limit the usefulness of the kinetic molecular theory in describing gas behavior are high pressure and low temperatures. This is because at high pressure, gas molecules are forced much closer together, reducing the empty space between them.
Consequently, the assumption that the volume of the particles themselves is negligible becomes less valid. Similarly, at low temperatures, the kinetic energy of the particles decreases, which leads to a reduction in motion and an increase in the significance of intermolecular attractions. Thus, the behavior of real gases deviates most from the ideal model under these conditions, making the kinetic molecular theory less applicable.