Determination of Copper Oxide's Empirical Formula: Experimental Data and Calculations, Lab Reports of Chemistry

Download Determination of Copper Oxide's Empirical Formula: Experimental Data and Calculations and more Lab Reports Chemistry in PDF only on Docsity! Date Performed: 9/20/07 Name: Elizabeth Luby Date Submitted: 9/27/07 Partner: Katie Therianos Instructor: Yang Liu Determination of a Chemical Formula Objectives  To determine the percentage composition and simplest formula for an oxide of copper by its reduction with methane gas at approximately 500 °C. This experiment is a study of stoichiometry. Experimental Data Mass of Test Tube- 17.774 g ± .0005 g Mass of Test Tube with Copper Oxide- 19.829 g ± .0005 g Mass of Heated Test Tube with Copper- 19.318g ± .0005 g Sample Calculations Mass of Copper Oxide= Mass of Copper Oxide +Test Tube- Test Tube =19.829 g ± .0005 – 17.774g ±.0005 g =2.055 g ± .0007g Mass of Copper= Mass of Heated Test Tube with Copper- Mass of Test Tube = 19.318 g ± .0005 g – 17.774 g ± .0005 g = 1.544 g ± .0007 g Mass of Oxygen= Mass of Copper Oxide – Mass of Copper = 2.055 g ± .0007g - 1.544 g ± .0007 g = 0.511 g ± .001 g Mass Percent of Copper= (Mass of Copper/ Mass of Copper Oxide) = 1.544 g ± .0007 g x 100 =75.13% ± .04% 2.055 g ± .0007g Mass Percent of Oxygen= (Mass of Oxygen/ Mass of Copper Oxide) = .511 g ± .001 g x 100 = 24.87 % ± .05% = 2.055 g ± .0007 g Mols of Copper= (Grams of Copper/ Grams per Mol of Copper) = .511 g ± .001 g = .02430 mols ± .00001 mols 63.55 ± .001 g/mol^-1 Mols of Oxygen= (Grams of Oxygen/ Grams per Mol of Oxygen) = .511 g ± .001 g = .0319 mols ± .00006 mols 16.00 g ± .001g Mol Ratio= (Mols of Oxygen/ Mols of Copper) = .0319 mols ± .00006 mols = 1.31 mols ± .003 mols ≈ 1:1 mol ratio .02430 mols ± .00001 mols Empirical Formula= CuO due to 1:1 mol ratio Results and Conclusions Mass of Copper Oxide 2.055 g ± .0007g Mass of Oxygen 0.511 g ± .001 g Mass of Copper 1.544 g ± .0007 g Mass Percent of Oxygen 24.87 % ± .05% Mass Percent of Copper 75.13% ± .04% Mols of Oxygen .0319 mols ± .00006 mols Mols of Copper .02430 mols ± .00001 mols Empirical Formula CuO The empirical formula for the Copper Oxide is CuO due to the one to one ratio of mols. Although the real ratio was 1.31 to 1 we round due to experimental uncertainty to the closest whole number. The ratio was found by dividing the mols of oxygen by the mols of copper. The mols of each were found by dividing the mass of the amount found in the experiment by the amount of mass found in one mol of the element. The percent composition of each element is found by dividing the mass of that element by that of the Copper Oxide. In the experiment, there were about three times more grams of Copper than Oxygen.