Which of the following statements best defines the theoretical yield of a reaction? The ratio of measured yield over actual yield
The amount of product measured after a reaction
The ratio of measured yield over stoichiometric yield
The maximum amount of product that can be obtained

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.