Growing Crystals Lab
Solubility in water is different for every substance. This lab will be used to investigate the ability to grow
crystals of CuSO4 in a saturated solution of CuSO4. Saturated solution means that the maximum amount
of solute (CuSO4) has been dissolved in the solvent (H2O). If you dissolve more than normally would be
allowed by increasing the heat of H2O you can get crystals to form when the solution is slowly cooled.
This lab will go through the process of getting a saturated solution to produce beautiful crystals.
You will be using different concentrations of a saturated solution to determine which ratio of CuSO4 to
water will yield the best crystals.
Additional Information:
http://www.stevespanglerscience.com/lab/experiments/instant-hot-ice
http://www.thenakedscientists.com/HTML/articles/article/science-of-snowflakes
http://www.seas.upenn.edu/~chem101/sschem/solidstatechem.html
Beginning Question: (decide amongst your group)
Hypothesis:
Safety Concerns:
Procedure: Day 1
1. Make your 100ml solution according to your group’s assignment using a graduated cylinder and
place it in a 250mL beaker.
2. Continue to heat (<70oC) and stir the solution until all of the CuSO4 has dissolved.
3. Pour the solution into two clean Petri dishes (approximately half in each) and cover each one
with Petri dish cover.
4. Place your Petri dishes against the wall and leave them over night.
5. Show your work for the molar concentration of your solution on the paper next to window.
Day 2
6. If you have a large crystal proceed to step 7, if not continue below
a. Dump your solution into a 250mL beaker and you will need to either dilute your original
solution or add additional solute to your solution to get an overall concentration of
2.0M. Remember the steps involved in Making Solution.
b. Repeat steps 2-5
7. Retrieve your Petri dish and evaluate your crystals. Remove the crystal of your choice from the
Petri dishes.
8. Record the height, length, width and weight of your crystal.
9. You need to make your solution saturated again in order to continue to grow your crystal so you
need to measure out the weight of the crystal you removed using freshly ground CuSO4 and
replenish the solution with that amount.
10. You also will have to replenish some water that was lost to evaporation during the night so,
after adding the replacement CuSO4 to the solution, fill the graduated cylinder back to originally
recorded volume.
11. Heat the solution to dissolve all of the CuSO4
12. Tie a piece of thread around your crystal and suspend the crystal in a 150ml beaker.
13. Suspend the crystal in your newly saturated solution in the beaker once its temperature is lower
than 30oC. Make sure the crystal is completely submerged but is not touching the bottom of the
beaker.
14. Place your beaker near the window overnight.
Day 3
15. Pull your crystal out of the solution and place it on a paper towel to remove your liquid from it.
16. Record the measurements of your crystal: height, length, width and weight.
17. Repeat steps #10-14. Remember to replenish the amount of CuSO4 that was used overnight
which would not be the whole weight of the crystal but rather the change in mass.
Observations:
Claims/Evidence: