CHEM
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# Let water escape 7 heat the crucible gently a do this

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Cover the crucible slightly with lid. Let water escape! 7. Heat the crucible gently a. Do this by holding the burner and move it from side to side for about 10 minutes. 8. Adjust the flame to high a. Heat the crucible by moving it from side to side again for another 10 minutes. 9. After 20 minutes , move the lid using the crucible tongs. a. Continue heating for one more minute b. Turn off the burner by closing the gas valve c. Set the crucible on a piece of wire gauze d. Place the lid back on and allow cooling. Do not place the hot crucible on bench top 10. Weigh the crucible a. Record the mass of the crucible Data and Calculations:

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Course: 1251L/25 Experiment: Identification of a Hydrate by Water Content Laboratory Report # 3 Possible Hydrates Molar Mass H 2 O Calculations % of water in hydrate Sr(NO 3 ) 2 *H 2 O 87.62 + 14.01(2) + 15.999(6) = 211.634 15.999 + (2)1.008 = 17.007 Na 2 CO 3 *10H 2 O 2(22.989) + 12.01 + (3)15.999 = 105.985 (20)1.008 + (10)15.999 = 180.15 MgSO 4 *7H 2 O 24.31 + 32.07 + 15.999(4) = 120.376 (14)1.008 + (7)15.999 = 126.105 CaSO 4 *2H 2 O 40.08 + 32.07 + (4)15.999 = 136.116 (4)1.008 + (2)15.999 = 36.03 LiCl*H 2 O 6.94 + 35.45 = 42.39 (2)1.008 + 15.999 = 18.015 Substance 648 1. Mass of empty crucible: __25.03g_ _ 2. Mass of crucible and hydrated salt: __27.23g__ 3. Mass of hydrate: __2.20g___ 4. Mass of crucible and contents after heating: __26.16g__ 5. Mass of anhydrous salt: __1.13g ___ 6. Mass of water released: __1.0g____ 7. Calculations of % water in hydrated salt: __48.64%_ Conclusion: 1. By consulting the % of water in hydrated salts in the chart, we arrived at the conclusion that our substance was MgSO 4 *7H 2 O. 2. To calculate the theoretical percent of water in each of the hydrates you must find the molar mass of the first compound then add it to the molar mass of the water to get the total molar mass of the two compounds. You then divide the molar mass of the water by the total molar mass to get the percent of water. Chemical equations Sr(NO 3 ) 2 *H 2 O(s) ->Sr(NO 3 ) 2 (s) + H 2 O(g) Strontium nitrite hydrate Na 2 CO 3 *10H 2 O(s) -> Na 2 CO 3 (s) + 10H 2 O(g) Sodium carbonate decahydrate MgSO 4 *7H 2 O(s) -> MgSO 4 ( s) + 7H 2 O(g) Magnesium sulfate heptahydrate CaSO 4 *2H 2 O(s) -> CaSO 4 (s) + 2H 2 O(g) Calcum sulfate dehydrate LiCl*H 2 O(s) -> LiCl(s) + H 2 O(g) Lithium chloride hydrate
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• Fall '12
• Rabinovich
• Chemistry, Mole, Magnesium sulfate, Water of crystallization, Clathrate hydrate

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