How many mL of an NaCl solution with the concentration of 0.35 mole/L do you need to make a 700 mL solution with the concentration of 0.15 mole/L?

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.

they are all solids.