[omar01]

Hi everyone,
To be brief, I'm growing crystals for a chemistry project. I created my first solution and it all went well, but not fro my second.
I diluted 29g of copper sulfate in 100ml of water at 40° to create a saturated solution. when I left the solution for a day (like i did the first time) the solution didn't crystallize and instead it left a sort of powder.
It would be helpful if there is an explanation for the formation of this powder.

thank you in advance,

[Hunter2]

Same topic

http://www.chemicalforums.com/index.php?topic=83544.0

[jeffmoonchop]

for the best crystals you need to slow down the crystallisation process. try decreasing the temperature more slowly. If you cool too quickly your product will crash out in lots of nucleation sites. The crystals will only grow until the solution is no longer supersaturated. If there are already a lot of small crystals they wont grow very large. Slowing it down only creates one or a few nucleation sites so one larger crystal. Its all to do with metastable zone widths and magnitude of supersaturation. also if there are impurities in the solution it can cause lots of small crystals. Purer is better.

[omar01]

Hi thank you for your help, but if i left the solution cool down at room temperature (if i understand correctly this won't be cooling it too fast)
in addition, i will use this opportunity to ask you another question : if i want to create more solution can I make it with the crystals formed from the first time, if yes do i use the same mass as with the powder.   

[Hunter2]

Of course you can use the crystalls again to get more solution.

[omar01]

thank you that was really helpful