Lab Report Chem

Formal Lab Report #1
I. Basics Title of the Experiment: The Empirical Formula of an Oxide Authors: Section Number: Chemistry Location and Date
II. Abstract The aim in this lab was to determine the empirical formula of an oxide of magnesium through combustion in air. This was achieved by heating an established mass of magnesium in air inside of a crucible, ultimately attaining a compound that contained Mg and O. The major result of the experiment was the empirical formula of the oxide of magnesium.
III. Introduction An empirical formula is defined as a formula that gives the simplest ratio of the relative number of atoms in a compound. And as stated before, the goal for this lab was to ascertain the empirical formula for an oxide of magnesium. The formula was acquired by obtaining a compound that contained both magnesium and oxygen. This was done through combustion in air. Having determined the mass of magnesium before the combustion made it possible to determine the mass of the oxygen present in the compound by simply subtracting magnesium 's mass from the total mass of the compound. Discovering the two masses allowed one to convert those masses into moles and then derive the mole ratio between the elements. The mole ratio, after having been converted into a whole number, brought about the subscripts for the elements in the formula. Altogether, this provided the empirical formula of MgO.
Essentially, this is important because knowing the that the empirical formula for the compound is MgO provides one with insight of how the compound is arranged.

IV. Materials and Methods The materials in this experiment were a support stand, an iron ring, a wire triangle, a Bunsen burner, matches, a porcelain crucible and its cover, crucible tongs, wire gauze, a medicine dropper, a balance, a .096 g Mg coiled ribbon, and 10 drops of distilled water. The set up for the experiment was the support stand with a ring attached to it, and a wire triangle placed on top. The Bunsen burner was placed about an inch below the ring so the flame would easily heat the crucible (which was always placed at an angle on top of the triangle, and the lid was left slightly ajar). The first step for the experiment was to clean the porcelain crucible and lid by heating it for five minutes. The crucible was eventually weighted after it had cooled down. Next, the mass of the magnesium, crucible and lid was taken. The combustion of magnesium began subsequently. To prevent the loss of the product (the oxide of magnesium), the lid was to completely cover the crucible once white smoke appeared. After the smoke was no longer present, the crucible was strongly heated for ten minutes. Next, the crucible and lid had to cool down again, so that ten drops of distilled water could be added to the crucible. This was done because the combustion of Mg in air caused some atmospheric nitrogen to react with Mg. The effect the compound had with water would dispose of the atmospheric nitrogen and turn it into the oxide of magnesium. A total of fifteen minutes of heating followed this step. Finally, after the crucible had cooled down, the mass of the crucible plus the compound compound was taken in order to determine the mass of the compound. The empirical formula was now notably feasible; for all that needed to be done was to follow the simple steps discussed in the introduction.
V. Results and Calculations *See attached paperwork for data* Although this experiment mainly requested quantitative data to be recorded, I did observe several obvious signs that this was a chemical change. Some of them were: the change in temperature of the metal, the change in color (from sliver to white), the change in texture (from shiny and smooth, to grainy and brittle), there were also gas emissions (the white smoke).
IV. Discussion/Conclusion My obtained empirical formula for the oxide of magnesium was MgO. And according the the research I have done, that is in fact the empirical formula for the compound. I believe the greatest source of error, in my case, was the fact that I was unable to distinguish the white smoke emerging from the crucible while it was being combusted, and therefore I most likely lost some o f my product. And even though it was undesired, the loss of some of the product ended up not affecting my final results that much because I still obtained the correct empirical formula. Everything else ran very smoothly throughout the experiment, so I really don’t have any suggestions regarding any possible changes. I definitely believe this experiment was a success because I accomplished the goal of the lab and I obtained the desired results (a correct empirical formula). With this investigation I learned that it is in fact possible to combust magnesium in air because there is oxygen gas present in air, (hence the presence of oxygen on the compound MgO). Moreover, this lab also helped me to become more comfortable determining the empirical formulas for compounds. Overall, I think this experiment provided me with great learning experience with the concept of the empirical formula.
VII. References "Chemical Reaction." Encyclopedia. Today’s Science. Facts On File News Services, n.d. Web. 6 Mar. 2011. <http://www.2facts.com/article/xch111300a>. Neidig, H. and Spencer, J. Signature Lab Series. The Empirical Formula of an Oxide. Ohio: Cengage Learning, 2008. Print.

References: "Chemical Reaction." Encyclopedia. Today’s Science. Facts On File News Services, n.d. Web. 6 Mar. 2011. <http://www.2facts.com/article/xch111300a>. Neidig, H. and Spencer, J. Signature Lab Series. The Empirical Formula of an Oxide. Ohio: Cengage Learning, 2008. Print.