Answer :
They made an approximation of the perfect one and then with it's help they conclude that these are the deficiencies in the real one ..
for more understanding you can take the example of anything that is made for instance
Take an ideal student : we consider an ideal student is the one who never gets late in doing any taks who so responsible and always first in everything,so on ....
and then we compare this to all students and then catagorize the students .. the students closer to this shows ideal behavior much ideal on specific conditions like Hydrogen shows close to ideal one but no one in actual is same as ideal one everyone has some flaws ...
Explaination:
Scientists often derive their calculations and theories using ideal gases because the ideal gas model provides a simple and convenient framework for understanding the behavior of gases. The assumptions of the ideal gas model make the calculations more tractable and allow for the derivation of analytical expressions and mathematical relationships.
The ideal gas model assumes that gas particles have negligible volume and do not interact with each other. It also assumes that the gas particles follow Newtonian mechanics and have elastic collisions. While these assumptions do not hold true for real gases, they provide a reasonable approximation under many conditions, especially at low pressures and high temperatures.
By using the ideal gas model, scientists can develop fundamental gas laws such as Boyle's law, Charles's law, and the ideal gas law. These laws provide useful relationships between pressure, volume, temperature, and the amount of gas. While the ideal gas model may not perfectly describe real gases, it often provides accurate predictions in practical situations, particularly when the gases are not highly compressed or near their condensation points.
It's important to note that scientists are aware of the limitations of the ideal gas model, and more sophisticated models have been developed to describe the behavior of real gases in specific situations. These models take into account factors such as intermolecular forces, non-negligible particle volumes, and deviations from ideal behavior. However, the ideal gas model remains a valuable starting point and a useful approximation for many calculations and applications in science and engineering