Lab+2+formula+of+hydrate


 * __ Name: __** Cullen Orengo


 * **__ Title /Date: __** Lab 2: The Formula of a Hydrate **10/26/2011**


 * **__ Purpose: __** To learn about hydrates and to determine the number of waters of hydration in a hydrate.
 * Teacher Comment: More detail. **
 * **__ List of Materials: __** Small hot plate, 10 x 75-mm culture tubes (11), Wire test tube clamp, glass stirring rod, Thin-stem transfer pipette, Bunsen burner, Wire screen with ceramic center (for cooling tubes). Reagents include calcium sulfate, Cobalt(II) chloride, Copper(II) chloride, Copper(II) sulfate, Nickel(II) chloride, potassium carbonate, Potassium chloride, sucrose (table sugar) and unknown hydrate.


 * **__ Safety Considerations: __**** 1.) ** Chemical splash-protective eyewear must be worn at all times in the laboratory Cobalt compounds are moderately toxic. **2.)** Wash your hands thoroughly with soap and water before leaving the laboratory. **3.)** Hot and cold glassware look alike. Be careful handling the test tubes and watch glasses in this experiment

**__ Part A __** Put a hot plate on the low setting. Put small amounts of all known solids into 7 different 10 x 75-mm culture tubes. If the solids are not a fine powder, crush the solids into a fine powder. Heat the bottoms of each tube on the Bunsen burner flame. Observe and record any changes. If water is lost from the compound during heating, you should notice condensation collecting near the top of the tube. This indicates whether or not the compound tested is a hydrate. Record what is seen in each tube. After the test tubes have cooled, add about 1 mL of water to each one using a thin-stem pipette. Stir and observe. If the substance is a hydrate, it should dissolve and give a substance close in color to the original. =Part B= Once you have marked the tubes for identification, carefully weigh (+/- 0.001g) each of your three remaining tubes. Put about 0.4 g of the unknown hydrate into every tube. They do not need to be equal. Using a clamp, hold the tubes one at a time in the flame of a small Bunsen burner. You must heat for at least 15 minutes. Let the tubes cool to room temperature and weigh them. Record each mass.
 * **__ Procedure: __**

__ Data Table(s): __
 * * = ** Condensation ** ||
 * **__ Solid __** ||  **__ Appearance Before __**  ||  **__ Appearance after __**  ||  **__ Hydrate? __**  ||  **__ Reasons __**  ||
 * Calcium Sulfate || White/ powdery || White/ chunky || No  ||  Nothing  ||
 * Cobalt(II) Chloride || Fuchsia || Deep purple/ * || Yes  ||  Back to original form *  ||
 * Copper(II) Chloride || Turquoise || Green then brown/black || Yes  ||  Back to original from   *  ||
 * Copper(II) Sulfate || Bright Blue || Gold-white/ * || Yes  ||  Back to original form   *  ||
 * Nickel(II) Chloride || Lime green || Orange/ brown || Yes  ||  Back to original form   *  ||
 * Potassium Carbonate || White grainy like snow || Gray/ ashy || No  ||  Nothing  ||
 * Potassium Chloride || White/ powdery || No reaction || No  ||  Nothing  ||
 * Sucrose || White/ powdery || Burnt/ black sludge || No  ||  Nothing  ||
 * Teacher Comment: Don't put conclusions about the data in the data table. **


 * **__ Prelab questions: __**

1.) a.) ** __Hydrate__: ** A compound, usually crystalline, with water molecules that are chemically bonded to another element. b.) The dot shows that the molecules are together. 2.) **__Anhydrous:__** Contains no water. 3.) a.) If the hydrate in part B is not heated enough to get rid of all the waters of  hydration, then the calculation of the number of hydration will not be accurate because there will still be waters in the hydrate.

1. Of the eight tested solids, four of them were hydrates. These include Cobalt(II) Chloride, Copper(II) Chloride, Copper(II) Sulfate and Nickel(II) Chloride. In each of the four, condensation around the top of the test tubes formed and when water was added to them, they went back to their original form. 2. a. **__ Tube 1: __** 22.1646g – 21.2269g = **.9377g** **__Tube 2:__** 18.7393g – 18.1069g = **.6324g** **__Tube 3:__** 22.1240g – 21.0897g = **1.0343g** b. **__ Tube 1: __** percent composition = (mass tube w/ substance) – (mass tube after heated and cooled) / (mass tube w/ substance) x 100 = (22.1646g – 21.2269g) / (22.1646g) x 100 = **4.23061% __Tube 2:__** (18.7393g – 18.1069g) / (18.7393g) x 100 = **3.37472%__Tube 3:__** (22.1240g – 21.0897g) / (22.1240g) x 100 = **4.67501%** 3. Al(NO3)3 + 9H20 = Al(26.98g) + 3N(42.021g) + 9O(144g) + 9H(18.1422g) + 9O(144g) = 375.1432g **GFM = 375.1432g** a. ** GFM of H2O ** =2H(2.0158g) + O(16g)= **18.0158g __Tube 1:__** .9377g H2O x (1 mol H2O) / (18.0158g H2O) = .**0520 mol __Tube 2:__** .6324g H2O x (1 mol H2O) / (18.0158g H2O) = **.0351 mol** **__Tube 3:__** 1.0343g H2O x (1 mol H2O) / (18.0158g H2O) = **.0574 mol** b. ** GFM of Al(NO3)3 = ** = Al(26.98g) + 3N(42.021g) + 9O(144g) **= 213.001** **__Tube 1:__** 21.2269g Al(NO3)3 x (1 mol Al(NO3)3) / (213.001g Al(NO3)3) = .**099656 mol Al(NO3)3 __Tube 2:__** 18.1069g Al(NO3)3 x (1 mol Al(NO3)3) / (213.001g Al(NO3)3) **= .085008 mol Al(NO3)3 __Tube 3:__** 21.0897g Al(NO3)3 x (1 mol Al(NO3)3) / (213.001g Al(NO3)3) = **.099012** **mol Al(NO3)3** c. **__ Tube 1: __** .0520 mol H2O : .099656 mol Al(NO3)3 = (1 : 1.9) **__Tube 2:__** .0351 mol H2O : .085008 mol Al(NO3)3 (1 : 2.4) **__Tube 3:__** .0574 mol H2O : .099012 mol Al(NO3)3 (1 : 1.7) 4. a. **__ Tube 1: __** 1 mol H2O : 2 mol Al(NO3)3 **__Tube 2__** 1 mol H2O : 2 mol Al(NO3)3 **__Tube 3__** 1 mol H2O : 2 mol Al(NO3)3 b. **__ Tube 1: __** **__2__**Al(NO3)3 **. __1__**H2O **__Tube 2:__** **__2__**Al(NO3)3 **. __1__**H2O **__Tube 3:__** **__2__**Al(NO3)3 **. __1__**H2O 5. One reason may have been not heating for a sufficient amount of time. Another could be not letting it cool off for a long enough period of time. 6. a. CuCl2 was turquoise and CuSO4 was bright blue. b. CuCl2 was green that turned to a brown/black and CuS04 was gold- white colored. c. Sodium Chloride is white and potassium chloride is white. d. It will be attracted to
 * ** Analysis and Conclusions **
 * Teacher Comment: Sig figs and your answer doesn't make good sense. **


 * Teacher Comment: Seems to end abruptly. Remainder of conclusion and stuff? Always proof read. 32/50 **