Final answer:
An ideal gas behaves as such under conditions of high temperature and low pressure, where the gas particles' volume and intermolecular attractions are negligible. Real gases approximate this behavior but may deviate under very low temperatures or high pressures.
Step-by-step explanation:
For a gas to be classified as ideal, certain conditions must be met. An ideal gas is a hypothetical substance that obeys the ideal gas law, which assumes that the gas particles are point particles with no volume and do not exhibit intermolecular attractions. Therefore, the conditions necessary for a gas to behave ideally are when the gas is at high temperature and low pressure.
Under these conditions, the particles move rapidly, and the space between them is so large relative to their size that their volume and the attractive forces between them can be considered negligible. These factors contribute to the gas exhibiting behavior close to that predicted by the kinetic molecular theory and the ideal gas law. However, it's important to note that real gases only approximate ideal behavior and may deviate from it at very low temperatures or high pressures.