How to make Zinc Sulfate Crystals?

Question

Hi, I'm currently doing an experiment. I'm trying to grow Zinc Sulfate Crystals at home. I'm using Zinc Sulfate Monohydrate (ZnSO4⋅H2O) --- it is what I ordered from Ebay. I don't know if my purchase was right or not, for there are other types of hydrates. I just happened to order the monohydrate without thinking. 

Steps I took:

1. In a small pot, I brought water to a boil.
2. I added the Zinc Sulfate monohydrate till I saturated the water with it.
3. I believe I saturated it.
4. I left the pot to cool off for 8 hours.
5. The experiment failed to produce crystals.

I'm wondering what I'm doing wrong. Did I buy the wrong ZnSO4⋅H2O? The same experiment I tried before, but with CuSO4.5H2O, and followed the same exact procedure and crystals were produced by the copper sulfate pentahydrate solution.

I wonder what I'm doing wrong? I'm a newbie at chemistry. I love chemistry.

All help will be greatly appreciated.

Answer 1

Not sure why you want to make ZnSO4 crystals, when you already have them  from Ebay.  But, nonetheless, you know that ZnSO4 (anhydrous, or ZnSO4⋅H2O) is soluble in water.  So, to saturate the solution isn't quite good enough.  You need to SUPER saturate it.  After that, you might try adding ethyl alcohol to precipitate the CuSO4, or cool it (as you did oer 8 hours).  Or you could "seed" the solution with a crystal or two of ZnSO4.  Short of that, I'm not sure how you can do it.  The problem is the solubility.  Again, make a supersaturated solution (if you think it is saturated, add more).  Then let it cool.  Good luck.