Questiu
What quantity of gas, in moles, is contained in 3.22 L at STP?

1.78molsO2*22.4LO2 divide by 1mole O2 =33.9Lo2

Explanation: This conversions relies on the fact that a mole of gas at STP has a volume of 22.4 L. It is important to note, however, that if the conditions of the gas are different this conversion will NOT work. Under those conditions you must use the ideal gas law to convert between moles and liters.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.