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Student Name Sharita JOhnson Student ID 169279 Lesson The Mole Concept: Chemical Formula of a Hydrate Institution John Tyler Community College Session Summer 2021 Course CHEM 101 - R81S Instructor Kulsoom Quraishi
Final Report
Exercise 1
CHEM 101 - R81S
The Mole Concept: Chemical Formula of a Hydrate
cup + KAI(SO ) +H O=4.4g
cup + KAI(SO ) = 3.4 g KAI(SO )
1g / 258.21 g/mol .0038 moles of KAI(SO )
1. Calculate the moles of anhydrous (dry) KAl(SO ) that were present in the sample. Show all work including units.
4 2
4 2 2
4 2 cup = 2. = 1g of 4 2
4
1g/18.006=.0555 moles of h O ratio- .05/.00387 = 12.91 = 13:1 H O : KAI(SO )
2. Calculate the ratio of moles of H O to moles of anhydrous KAl(SO ). Show all work including units.
Note: Report the ratio to the closest whole number.
2 4 2
2 2 4 2
KAl(SO ) •13H O 13 moles of water
3. Write the empirical formula for the hydrated KAl(SO ) , based on your experimental results and answer to Question 2. Show all work including units.
Hint: if the ratio of moles of H O to moles of anhydrous KAl(SO ) was 4, then the empirical formula would be: KAl(SO ) •4H O.
4 2
2 4 2 4 2 2
4 2 2
Alum hydrate is the white crystalline solid after heating it will began melting because of the h O of hydration present in it. Then again solid will remain or stay in the aluminum cup once all the water is leaving in the form of vapors or has it evaporates
4. Describe any visual differences between the hydrated sample and the dried, anhydrous form.
2
Object Mass (g)
Aluminum Cup (Empty)
Aluminum Cup + 2.0 grams of Alum
Aluminum Cup + Alum After 1st Heating
Aluminum Cup + Alum After 2 Heating
Mass of Released H O
Molar mass of H O
Moles of Released H O
nd (^) 3.
