After that, dissolve the sample in 2 mL of deionized water and shake the test tube for 1 to 1 ½ minutes to dissolve the solid. Place another dry test tube in a 50mL beaker and weigh it. Find a bottle of barium iodide and record the name and molar mass. Then, weight out either anhydrous barium iodide or barium iodide dehydrate into this test tube and dissolve is it in 2 mL of deionized water. Pour the contents of one of the test tubes into the other and a reaction should occur and you should see a white precipitate of barium sulfate form.
In the first part, five 100 mL flasks of 5 mL ligand solution, 5 mL 2 M sodium acetate, 4 mL 3 M NH2OH, and 1-5 mL Fe2+ solution are diluted with water. The absorption spectrum for varying concentrations of Fe2+ are measured using a spectrophotometer and the data is graphed in Excel. The slope of the line is ε in the Beer-Lambart equation A = εcl. In the second part of the experiment, eleven flasks containing diluted stock solutions of Fe2+ and ligand are mixed with 5 mL 2 M sodium acetate and 4 mL 3 M NH2OH and diluted with water. The absorption spectrum is measured using a spectrophotometer and the data is graphed in Excel.
In another flask 50-mL of ice water was deposited with three-drop phenolphthalein. Using a volumetric pipet 50-mL of the 1-bromopropane was added into the empty flask in the bath. By the same method 50-mL of potassium hydroxide was delivered to the same flask while swirling the contents and remaining in the water bath. A 10-mL aliquot was immediately removed from the mixture and added to the ice water containing the phenolphthalein. When the pipet was half emptied into the ice water a timer was started.
To do this, first take the number of drops used to achieve the monolayer (1 drop) and convert it to mL using the calibrated number of drops per mL. Then multiply the number of grams of sodium stearate per milliliter of solution. Finally, convert to moles through the molar mass of sodium stearate. HINT: The molar mass of sodium stearate is 296.5 g/mole. Answer = 1.06*10^7 moles/top layer 5.
SYNTHESIS 3 Purifying an unknown solid by recrystallization involved preparing cobalt amine chloride product. By adding five grams of cobalt II chloride into 20ml of 9M HBR in 250 mL beaker, plus 15 mL of deionized water. Dissolving the compound within pure water, filtration by gravity and adding two grams of activated charcoal and 25 mL of concentrated. Cooled after heating and additional six mL of 30 percent hydrogen peroxide. Filter by suction then collect the dark solid.
The flasks were thoroughly cleaned with distilled water. 3. Samples of the Ammonium Persulfate ((NH4)2S2O8), Potassium Iodide (KI), Ammonium Sulfate ((NH4)2S2O4), Potassium Nitrate (KNO3), Sodium Thiosulfate (Na2S2O3), and Starch were placed in separate Erlenmeyer flasks. 4. Each flask was labeled according to its content (i.e.
0.00512 * 500 = 2.56 c. 0.00806 * 319.9= 2.56 d. 0.00806 * 319.9 = 2.56 500 mL =0.5 L e. 0.0161 * 500 / 2 =2.56 4. Exercise 4: a. 0.250M; 250 mL 0.25 L (0.25) (0.25) = 0.0625 moles ZnI2 b. Prepare the solution by dissolving 19.95 grams of Zinc Iodide with 250 mL of water. c. Prepare the solution by dissolving 38.90 grams of ZnI2 with 500 mL of water.
If 0.100 mol of hydrogen iodide is placed in a 1.0 L container and allowed to reach equilibrium, find the concentrations of all reactants and products at equilibrium. 2 HI (g) === H2 (g) + I2 (g) Ke = 1.84(10-2 [H2]=[I2]= 1.07(10-2 mol/L, [HI]=7.86(10-2 mol/L 6. A 1.00 L reaction vessel initially contains 9.28(10-3 moles of H2S. At equilibrium, the concentration of H2S of 7.06(10-3 mol/L. Calculate the value of Ke for this system.
Next, obtain a 5 mL serological pipet and thoroughly rinse it with the buffer solution, then discard the buffer solution into the 250 mL beaker. Now, use the pipet to distribute 5 mL of the buffer solution into three 50 mL beakers. Be sure that the 50 mL beakers have been cleaned are dried prior to this. Next, locate the three pre filled burets in the lab room. Find the buret labeled 1.0M HCl and add exactly 1.00 mL of HCl to just one of the three 50 mL beakers with buffer solution already in them.