First one to answer gets !

according to current scientific thinking, how did the solar system that contains earth form?

The dust and gas particles of a slowly rotating nebula gradually came together to form a cloud with a huge central bulge surrounded by a flat ring of dust and gas. The sun was formed from the material in the bulge. The flat ring became several rings. In each ring, a planet formed and continued to revolve around the sun in the plane of the ring it came from.

Explanation:

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%

it means there are 3 atoms of oxygen