How many moles of HCl are present in 0.70 L of a 0.33 M HCl solution? a
0.23 mol
Ob
0.38 mol
0.28 mol
Od
0.47 mol

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.