Which of the following is not sublimable?
Dry ice
Calcium chloride
Ammonium chloride

Calcium chloride

Explanation:

Sublimation is the process whereby a solid substance is converted to gas when heat is applied. Solid normally gets converted to the liquid phase before reaching the gaseous phase but these substances gets converted from solid straight to gas

Solid—> Gas

Dry ice( solid CO2) and Ammonium chloride undergo sublimation while Calcium chloride doesn't.

Ammonium chloride

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%