Coppin State College Department of Natural Sciences
Chemistry 101.001 Dr. Alfred N. Amah
Dr. P. Krishnan
Experiment V-DETERMINATION OF WATER OF HYDRATION
NAME______ID#______Date______Sec.002
Last First
Data Sheet
Weight of empty (MT) crucible ______
Weight of empty crucible and sample, g ______
Weight of sample, g ______
Weight of crucible and sample:
after first heating ______
after second heating ______
after third heating ______
Weight of water lost ______
Percent of water in sample ______(determined from this experiment).
Formula of anhydrous salt ______
Number of moles of anhydrous salt ______
Number of moles of water ______
Number of moles of water in the formula of the hydrate ______
Formula of hydrate ______
Procedure:
Weigh out 2-3 g of the hydrated salt in a crucible using a triple-beam balance. Heat the hydrated salt as directed by your Instructor until a constant weight is obtained. Calculate the weight in grams of water lost from the hydrated salt. From this inforomation, determine the value of (x) in the formula of the hydrated salt. The salt used in this Experiment is CuSO4 .xH2O. [ Hint: use the methods outlined in the text for the calculation of Empirical Formula] (Cu = 63.546; S = 32.066; O = 16.00; H = 1.00, Ca = 40.078)
grams moles mole ratio formula
CuSO4:
H2O:
Questions to answer and turn in to the Instructor after the experiment:
1. Copper sulfate forms several hydrates: CuSO4.H2O, CuSO4.3H2O, and CuSO4.5H2O. A student determined that an unknown CuSO4 hydrate lost 25.3% of its weight upon heating. Which hydrate did the student have? Show your work.
2. A commonly used hydrate of CaSO4 is plaster of Paris, which contains 6.21% water. What is the formula for plaster of Paris? Show your work.
3. Gypsum, CaSO4.2H2O is another hydrate of CaSO4. How much water would 5.00 g of gypsum lose if the water of hydration were driven off? Show your work.