In a presentation about measuring mass, one of your classmates states, "Two objects of the same size will always have the same mass.” Is this statement correct? Why or why not?

The statement is not correct.

Explanation:

If two objects have the same mass, their respective densities determine their volumes. By definition, density = mass/volume or volume = mass/density. Therefore if two objects have the same mass, the mode dense object (with higher density) will occupy less volume than the other object.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%