A compound, C20H28O, produces a 1H NMR spectrum with 11 distinct signals. The steps made by the integral trace measure 52, 17, 17, 26, 17, 25, 26, 9, 9, 35, and 8 mm. Complete the following table. Integral # Products
52 mm
17 mm
17 mm
26 mm
17 mm
25 mm
26 mm
35 mm
8 mm

Solution :

The smallest integer value represents the smaller number of protons.

In this case, in the given values, the smallest numbers are 8 mm and 9 mm, so both contains 1H each. Then next highest  value is 17 mm, which contains 1H more. Thus 17 mm contains 2H each. Then the next highest is 25 mm and 26 mm which contains 3M each and so on.

Thus the tables is :

Integral     Protons

52 mm          

17 mm            

17 mm            2

26 mm           3

17 mm            2

25 mm           3

26 mm           3

9 mm              1

9 mm              1

35 mm            4    

8 mm              1

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.