I don't understand the concept of an ideal gas? can anyone explain this to me?

Question

I know it is the characteristics of what the perfect gas would be, and that no such gas exist. What is the function of this concept?

Answer 1

Your question seems to be "why take the time to learn about a model that is wrong?"

If you are designing machinery that is very precise (like a steam turbine for power generation) a good model for a gas (water) should allow for useful predictions at the temperatures and pressures of interest. However, typically, a model will be empirical (based on curve fitting to experimental data) and only valid in a limited operation range of the variables.

If you want to extrapolate outside the experimental range, you need to develop theoretical models. Theoretical models have another advantage in that the parameters have physical meaning rather than just being "the coefficient that multiplies" some term in your regression. Theoretical models are validated by experimental data and other known valid theoretical models.

The ideal gas law is a theoretical model that treats a gas as a collection of non-interacting point masses. It is correct (and valid) in the limit of low gas density (low pressure, high temperature) because at low density there will be few gas particle collisions.
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Since the ideal gas model is valid in a certain parameter range for all gases, it may be used to help suggest the form of other empirical or theoretical models--any model that is useful in the low density limit must collapse onto the ideal gas model. Also, it is really simple, allowing for analytical solutions to be developed and compared to the limiting behavior of a more complicated model as a sanity check for the more detailed model.

Have you had any calculus? A "better" model than the ideal gas law is the virial equation of state, which basically says that the pressure is just a taylor series expansion in the molar volume. In the limit of small molar volume (small density), all the higher ordered terms of molar volume are negligible and the linear term is good enough (kind of like a linear approximation to a more complicated curve).

Answer 2

Ideal gas is a good approximation that lets you predict the behaviour of gas with a relatively simple formula.

the properties of an ideal gas are:
1) it's assumed that the gas particle don't interact
2) the gas particle have a negligible volume.

a gas like this will follow the PV=nRT rule pretty closely. most gases do this at low teperatures, and then you don't need more complicated equations to predict anything. At higher temperatures, the gas particles are too energetic and they interact with each other, causing deviation from the predictions.

Answer 3

It's a simplification. In low pressure (below 10 atm) and temperature above the critical temp of the gas it approximates reasonably well for most gases. Real gases have all sorts of interactions that make the system complicated.

Answer 4

PV=nRT

Ideal a gas should behave in the equation above however i doesnt. It gives you a easy generalized behavior which is easy to calculate and easy to explain. The real gas law is much more complicated and has many more degree of freedoms. To learn something new, its always easier to start with something basic and go on ferom there

Answer 5

The purpose is that it simplifies calculations involving gases.

For what it's worth, gases at STP (standard temperature and pressure) behave a lot like ideal gases - it's close enough for most calculations.

Answer 6

Many gases are nearly perfect. They obey the law PV = nRT well.

Answer 7

PV=nRT. function? use to measure the quantities (P, V, n, R (not really lol), T). then take deviation of V and P into account.