If a sample of a substance contains 9.03 x 1023 representative particles, how many moles does this represent? 0.5 mole 1 mole 1.5 mole 9 mole

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.