If 5.71 moles of ethane (C2H6) undergo combustion according to the unbalanced equation C2H6 + O2 → CO2 + H2O , how many moles of H2O is formed?

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.