If a pharmacist dissolves 1.2 grams of a medicinal agent in 60 ml of a cough syrup having a specific gravity of 1.20, what is the specific gravity of the product if the addition of the medicinal agent increases the syrup's volume by 0.2 ml?

Mass of medicinal agent taken = 1.2 g

the volume is 60 mL

Specific gravity = 1.20

So the mass of solution = specific gravity X volume = 1.20 * 60 = 72g

Now if we have increased the volume by 0.2 so the new volume = 60.2

New mass = 72 + 1.2 = 73.2  

Specific gravity = mass /  volume = 73.2 / 60.2 = 1.22 g/mL

the dependant variable is spilled water

the independent is the heat

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.