How many moles of nitrogen gas are needed to completely react with 6.00 moles of oxygen gas in the following reaction:

2 n2(g) + 3 o2(g) > 2 n2o3(g)

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.