Of the following substances, which one is NOT expected to dissolve in water? 1. C3H7OH 2. C7H16 3. KOH

Explanation:

Water is a polar solvent and hence can dissolve only polar solutes. Positive end of water attracts negative end of the solute and likewise negative end of water attracts positive end of the solute. This opposite attractions lead to dissolution.

In case of organic compound, water dissolve solute by forming hydrogen bond also.

Among the given, only is non-polar and cannot form hydrogen bond with water too.

Therefore, only is not expected to dissolve in water.

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%