Error Analysis: Single Displacement Reaction

Error Analysis
The percent error or percent yield between the theoretical yield of Cu produced and experimental value of Cu produced was approximately 107 %. One source of error, which was a scientific error, was that leaving the Cu precipitate in the cupboard for week allows dust to accumulate on the sample. When dust accumulates on the Cu precipitate for a period of one week, it adds additional mass when weighed. This is because dust has mass, and as more and more dust accumulate, the accumulation of dust will have a greater mass. As a result, the experimental mass of Cu produced would be greater than the theoretical value of Cu produced in the reaction since the precipitate weighed on the electronic balance is also considering the mass of

Moreover, another purpose was to learn how to use different lab techniques, such as filtration and proper heating of test tubes, in order to determine the mass of products produced by the reaction. Not only that, the experiment demonstrates how transition elements can often form more than one type of reaction due to their differently charged ions, like Fe. One of the key results of the experiment was that the percent yield was greater than 107%. Often times, the actual yield is less than the theoretical yield because there may be competing reactions, external conditions may not be ideally maintained, or the reactants are not pure. However, in this experiment, the actual yield was higher than the theoretical yield possibly due to the source of errors that dust accumulated on the precipitate or some of the precipitate reacted with other elements in the atmosphere. Another key result of the experiment was that the data indicated that the reaction involved 〖Fe〗^(2+)ions because the calculated Cu/Fe molar ratio was approximately 1.07, or rounded to 1:1. This mole ratio is closer and similar to the first equation Fe(s)+〖CuSO〗_4 (aq)→〖FeSO〗_4 (aq)+Cu(s), because the Cu/Fe molar ratio is also 1:1. Therefore, the reaction with 〖Fe〗^(3+)ions did not take place since its equation – equation 2 – has a Cu/Fe molar ratio of