What would happen to the rate of a reaction with rate law rate = k (NO)^2(H2) if the concentration of NO were halved?
A. The rate would be doubled.
B. The rate would be four times larger.
C. The rate would be one-fourth.
D. The rate would also be halved.

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.