Chemistry 221 with Professor Thomas Quale May 2012 Formal Lab Report
Abstract
An unknown sample, # 12-Green, was separated into its individual variable components, iron, ammonium chloride, silicon dioxide, and sodium chloride. The techniques used to separate the components of unknown # 12-Green, magnetism, sublimation, extraction, and filtration, were chosen based on the unique properties of each component. Using these separation techniques, each substance was extracted and the composition of unknown # 12-Green was 16% Fe, 15% NH4Cl, 59% SiO2, and 9% NaCl with a 1% uncertainty due to the loss of 0.0369g of the initial mass.
Introduction
A mixture is two or more substances (elements and/or …show more content…
The initial mass of unknown # 12-Green was recorded. The first substance separated from the mixture was iron based on its unique magnetic property. A magnet was used to extract the iron from unknown # 12-Green and the mass of the iron fillings was recorded. The next substance separated from the mixture was ammonium chloride based on its unique ability to sublimate. Unknown # 12-Green was heated with a Bunsen burner in a fume hood (note the special precaution) until the ammonium chloride was entirely extracted. The mass of the mixture was obtained to determine the amount of ammonium chloride lost due to sublimation and the mass of ammonium chloride in the mixture was recorded. Next, the extraction separation technique was used to separate the two remaining substances, silicon dioxide and sodium chloride. Extraction is used to remove a substance with a greater solubility from a substance with a lower solubility. In this case, silicon dioxide is not soluble in water while sodium chloride is. Therefore, approximately 20mL of deionized water was added to the mixture. The mixture was stirred until the sodium chloride was dissolved and the silicon dioxide had settled to the bottom of the dish. The filtration separation technique was used to separate the silicon dioxide from the sodium chloride suspended in water. The silicon dioxide collected in the filter paper was placed in the oven until it was …show more content…
These techniques were chosen based on the unique properties of each component to effectively separate them from unknown sample # 12-Green. The mass and percent compositions by mass for the individual components are shown in Table 1: Experimental Results. The percent yield and mass that is unaccounted for are shown in Table 2: Uncertainty Results. Based on comparing the initial and final mass, there was a 98.77% yield and, consequently, a 1.23% uncertainty in the results. Possible sources of the error are lost sample while collecting the iron filling with the magnet, while drying the sodium chloride, and while weighing the silicon dioxide. These sources combined probably resulted in a small loss of the initial sample and explain the unaccounted for