Bensalem High School Chemistry
Hydrate Lab
LAB COVER PAGE
Submitted by
Name _______________________________________ Period ____________
Grade ____________
Page 12
Hydrate Rubric
Page 13
Hydrate Lab Report Completed
Page 14
Data and Graph Moles verse water
15 Points
Page 15
Hydrate Abstract
20 Points
Page 16
Conclusion questions (each question is worth 2 points)
20 Points
55 Points Total
Determine the Percentage of Water in a Hydrate:
Introduction: Because salts are ionic, they have a tendency to gain water molecules. When this
happens, it is called a hydrate. We can find the % water by evaporating the salt.
Objective – Find the percent water in a hydrate.
Hypothesis: If the hydrate _________ has a percentage of ___________, then if I use 20 grams of
material, I would expect ________g of water to evaporate.
Procedure:
1.
2.
3.
4.
5.
6.
Measured the mass of a clean dry 250 ml Beaker:
_____________
Measure 20 grams of hydrated salt
_____________
Measured mass of the whole system( Beaker, spoon and hydate _____________
Heated beaker with hydrated salt for 3 minutes, before increasing heat. Increase
heat if necessary and continue heating for an addition 7 minutes. At that time, the
copper sulfate had turned a yellowish-white.
Removed Beaker from burner, and allowed to return to room temperature for
about 5 minutes. Measure Mass of system after 1st heating
_____________
Repeat steps 4 – 5 again and get a 2nd reading
_____________
Data Analysis:
Group
1
2
3
4
5
6
7
8
Grams of
Anhydrate
(salt) left
Grams of
water
evaporated
Graph: grams of copper sulfate (anhydrate) (x) vs. grams of water (y) The
slope will tell you the % of water in the salt molecule.
Sources of Error
1. For each of the following, state the effect (increase, decrease, no change) on the calculated mass.
a. All the reaction mixture was not transferred to the evaporating dish.
b. All the water was not evaporated during the heating process.
c. Some of the reaction mixture splatters out of the evaporating dish during the heating process.
d. Some of the hydrate is lost by decomposing the solid due to overheating the solid.
e. Soot for the burner is deposited on the Beaker during heating to evaporate the water.
f. Water is adsorbed by the zinc chloride during the cooling process but before the compound is
massed.
g. The beaker wasn’t completely dry before adding the 20 gams of hydrate.
h. Forgot to measure the spoon after evaporating the water for the 1st reading.
i. Calculate percent error and discuss where you error could be coming from
HOW TO WRITE AN ABSTRACT 20 Points
Introduction statement (reel the readers in with how the overall theme/hypothesis applies to life)
The objective of the lab is …………
My hypothesis for this lab is ………….because………………
I accomplished this by….(explain you procedure BRIEFLY)
Our data showed, based on graphs, (validate hypothesis, explain graphs, slope)
In conclusion, ……(summarize the objective and hypothesis)
Real life statement (connect the introduction statement to the last statement)
HOW IT APPLIES TO LIFE
1. Why do you use saline solution to rehydrate your eye?
2. Salts are used in detergents and become blue when you add.
3. Salt in restaurants always gets clumpy when its humid?
4. Keep chicken or turkey moist. Rub salt in the cavity of the bird before cooking.
5. Prevent sautés made with eggplant or zucchini from getting watery. Sprinkle salt on these vegetables before cooking.
6. Why put wet phone in a bag with rice?
cles. Epsom salt will work as
well
8. By wetting the sting and covering it with salt will bring soothing relief. If you are allergic to bees then you
should do what you normally do. The method just described will sooth and ease the pain.
Hydrate Abstract
Discussion Questions
Discussion Questions
1. What is the percent of water in CuSO4·5H2O(s).
2. What happened to the color of the product when you removed the water? What does
this indicate?
3. Real formula is CuSO4 * 5H20 – What is the moles of H20 if you have 1.8 moles of
CuSO4?
4. If you stopped experiment before all water was driven off, how would this affect your
percentage?
5. Write the name, formula, and molar mass of your hydrate.
6. How many grams will evaporate if you have 200 grams of Cobalt II Chloride
dehydrate?
7. Calculate how much water would evaporate if you had 10 grams of MgSO 4. 6H2O
8. Two practical purposes of anhydrous salts in everyday life