When a solution of beryllium sulfate and calcium hydroxide are mixed, what precipitate if any is formed

CaSO₄ (calcium suflate) is the precipitate formed

Explanation:

We can think the reactants:

BeSO₄ → Beryllium sulfate

Ca(OH)₂ → Calcium hydroxide

The reaction is:

Be₂SO₄  +  Ca(OH)₂  →  CaSO₄ ↓  +  Be(OH)₂

We call it as a double-replacement reaction because two ions exchange places from 2 compounds to form two new compounds.

Sulfates can always make precipitate with the elements from group 2, Ca, Ba and Mg.  

Hydroxides from group 2 are solubles, so we complete states:

BeSO₄ (aq)  +  Ca(OH)₂ (aq)  →  CaSO₄ ↓ (s)  +  Be(OH)₂ (aq)

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%