Whats the volume of 2.5 moles of hydrogen

At STP it would be 56 L

Explanation:

any gas at STP takes up 22.4 L and you have 2.5 moles

( 22.4 L/ 1 mole ) x 2.5 mole = 56 L

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.