Under which conditions are gases usually considered to be ideal?

Gases are typically considered to be ideal under high temperature and low pressure conditions. This is because, at high temperatures, the kinetic energy of gas molecules is increased, resulting in greater average speeds and more energetic collisions. Additionally, under low pressure, gas molecules are farther apart, which minimizes interactions between them and reduces the effects of intermolecular forces.

In these conditions, the assumptions of the ideal gas law — that gas molecules have negligible volume and that there are no intermolecular forces — become more accurate. As a result, the behavior predicted by the ideal gas law closely matches the actual behavior of the gas.

Under low temperature and high pressure, for example, gas molecules are more likely to be influenced by intermolecular forces and their own molecular volume, which leads to deviations from ideal behavior. High molecular weight alongside low temperature would also cause the gas to behave less ideally due to increased intermolecular interactions. Therefore, the statement that gases are ideal at high temperature and low pressure accurately reflects the conditions that lead to ideal gas behavior.