Empirical Formula Lab
Class: Chemistry 1405 Fall 2013
The aim of this Lab Exercise is to use the mass of a chemical and use that mass to find the amount of moles of the final product you can get using the empirical formula.
The empirical formula of a compound is the simplest whole-number ratio of the elements in the compound, which as you will discover, is a ratio of the moles of those elements. “Empirical” also means “experimentally determined”. In this experiment, we find the empirical formula of the oxide of magnesium. We will accomplish this task by reacting a massed amount of magnesium with the oxygen in the air. Knowing the original mass of magnesium and the final mass of the magnesium oxide, you can find the mass of the oxide portion. From these two masses, you can find the empirical formula, the ratio of moles.
1. Obtain a crucible and inspect it for cracks. Wash and dry it. 2. Place the crucible on a clay triangle support ring on the ring stand. After you have lit the burner, adjust the burner to provide a hot flame that touches the bottom of the crucible. Heat for about 5 minutes. This is part of the cleaning process. 3. Using the crucible tongs, move the crucible to the wire gauze for cooling. Let the crucible cool to table-top temperature. While you are waiting, obtain a sample of magnesium ribbon. Fold the magnesium into an accordion-like shape with about 1-2 cm folds. You can also use this time to write the “descriptors” for the rest of the data by reading ahead. 4. Use the analytical balance, mass the cooled crucible and record. Mass the crucible with the magnesium and record. By subtraction, find the mass of Magnesium and record this value. 5. Replace the crucible into the clay triangle. Heat crucible with the magnesium and record. By subtraction, find the mass of Magnesium and record this value. 6. Then heat the crucible (which contains the magnesium) into the clay triangle. Do not look directly...
Please join StudyMode to read the full document