20001549402000200660 Essays (912 words) - Laboratory Equipment

20001549402000200660 Empirical formula determination Lab # 66900096000 Empirical formula determination Lab # 6730005673725center Taylor Fitzgerald March 18, 20142420096000 Taylor Fitzgerald March 18, 2014 Short Form Memo-Style Lab Reports TO: Professor Michelle Sama FROM: Taylor Fitzgerald, CIT Student LAB PARTNER: Joe Toomey DATE: March 18, 2014 SUBJECT: Empirical Formula Determination Purpose: The purpose of this lab was to experimentally determine the empirical formula of magnesium oxide, the compound this is formed when magnesium metal reacts with oxygen. Summary: What I have learned in this lab is that the empirical formula that Joe and I gathered from this lab is Mg0, a 1:1 ratio. Procedures: During this lab to start each lab group sets up a ringstand with a ring, placing a clay triangle over the ring. There must be room under the ring for the Bunsen burner (approximately 2-3 inches). Next, connect the Bunsen burner to the gas outlet using rubber tubing. Once a group is given the okay by the instructor, the Bunsen burner may be turned on. Allow the flame to be about 1 inch. Next, dry a crucible by heating it over the flame of the Bunsen burner. Do not let the crucible glow red. Now using the tongs, remove the crucible from the triangle on the ring to a dry area at the work bench. Now the crucible and lid need to cool until each is at room temperature. This took my group approximately 15 minutes. Once they are at room temperature, weigh them both together on an analytical scale. While the crucible and lid are cooling, each group must collect a 25 cm piece of magnesium ribbon. Gently coil the ribbon the fit inside the crucible. My group coiled ours around a pencil. Now that the lid and crucible should be at room temperature, place the magnesium ribbon inside the crucible and place the lid on it. Each group will then measure and record the weight of the magnesium ribbon, crucible, and lid all together. Now, using the tongs, carefully return the crucible, magnesium ribbon, and lid back to the clay triangle above the Bunsen burner. Remove the lid but keep it nearby for the next step. Each group will heat the crucible and magnesium ribbon until the magnesium ribbon ignites. Be sure not to inhale or stare directly at the ignition. When the magnesium ribbon begins burning, place the lid back on top of the crucible using the tongs and remove the Bunsen burner from the area. After the ignition, glowing, and smoke have all disappeared, return the Bunsen burner underneath the crucible and being the heating process again. Remove the Bunsen burner and lift the lid on top of the crucible about every 2-3 minutes to check the reaction. After approximately 15 minutes or so, check to see if the reaction is completed. The magnesium ribbon should have changed to a light gray/white powder (magnesium oxide). If the ribbon material still remains after the 15 minutes, continue using the Bunsen burner until the magnesium ribbon is powdery. Now turn off the Bunsen burner and let the crucible and lid cool completely. Measure and record the combined mass of the crucible, lid, and magnesium oxide for one last measurement. Dispose of the magnesium oxide into the approved waste bucket provided by your chemistry professor(s). Lastly, clean up the group's entire bench area. Results: Item Mass Characteristics (shape/color) Empty crucible + lid 40.98 g N/A - No magnesium strip is involved yet Crucible, lid, and magnesium strip before heating 41.37 g Magnesium strip is present, shiny, silver Crucible, lid, and magnesium strip after heating 41.62 g White/gray powder What was the mass of the magnesium used? Magnesium = 0.38 g How many moles of magnesium were used? Moles of magnesium = (0.38 g / 24.30506 g/Mol) = 0.0156346045 Moles of magnesium Determine the mass of the magnesium oxide formed. 41.62 g - 40.98 g = 0.64 g Determine the mass of oxygen that combined with the magnesium. 41.62 g - 41.37 g = 0.25 g Calculate the number of moles of oxygen atoms that were used. (0.25 g / 15.99943) = 0.01563 Moles Calculate the ratio between moles of magnesium used and moles of oxygen used. Express the ratio in simplest whole-number form. 0.01563 : 0.01563 = 1:1 (ratio) 0.01563 : 0.01563 Based on your experimental data, write the empirical formula for magnesium oxide. MgO Calculate the percent error in your determination of the magnesium:oxygen mole