What is the concentration of 15 grams of NaCl in water to form a solution of 200 grams

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.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante