The topic of this lab experiment is the relationship between percent yields and limiting reagents, and how it relates to copper (II) sulfate and aluminum foil. The objective was to determine the limiting reagent in a reaction and calculate the percent yield. To understand this, fundamental concepts of percent yields and limiting reagents are essential. A percent yield is defined as the ratio of the actual yield, to the theoretical yield in a reaction, expressed as a percent (Haberer, Salciccioli, & Sanader, 2011). This is useful as several impurities in this reaction possibly contributed to the percent yield. Examples of impurities are competing side reactions, the incomplete removal of water from the sample, and aging chemicals which are not stored properly (Helmenstine, 2018). A limiting reagent, however, is the reactant completely …show more content…
Materials The amount of copper that was obtained was not the same as the mass expected, as it was significantly greater. This may be caused by side reactions, or if the elements that were used were not truly pure. These may be some reasons that caused the amount of copper to be greater, as the mass calculated should generally be close to, or less than the mass expected in pure reactions. The color of the solution was tinted green after this reaction was complete. This suggests that the reaction had some impurities with copper ions. Since the color of aluminum sulfate should be ideally clear, it is easily assumable that some copper ions dissolved into the solution. This is as Cu+ ions are green in aqueous solutions (Helmenstine, 2018). Therefore, the copper ions did not completely filter, creating a tinted green colored solution. Percent yield = (mass of actual yield )/(mass of theorethical yield) ×100% ≐(1.22 grams)/(0.7066 grams) × 100% ≐