The lab performed required the use of quantitative and analytical analysis along with limiting reagent analysis. The reaction of Copper (II) Sulfate, CuSO4, mass of 7.0015g with 2.0095g Fe or iron powder produced a solid precipitate of copper while the solution remained the blue color. Through this the appropriate reaction had to be determined out of the two possibilities. Through the use of a vacuum filtration system the mass of Cu was found to be 2.1726g which meant that through limiting reagent analysis Fe was determined to be the limiting reagent and the chemical reaction was determined to be as following:- CuSO4(aq) + Fe(s) Cu(s) + FeSO4(aq)
There were several purposes of this lab, the main ones were limiting reagent analysis, quantitative and analytical analysis, and techniques like vacuum filtration and weighing by difference. The main focus of the lab was the oxidation-reduction reaction between Copper Sulfate and Iron Powder and there were two possible reactions based on the charge of iron once it gets oxidized by copper. The two possible balanced reactions are – CuSO4 (aq) + Fe(s) Cu(s) + FeSO4 (aq) [I]
3CuSO4 (aq) + 2Fe(s) 3Cu(s) + Fe2(SO4)3(aq) [II]
Through the possible reactions, one of the best way to determine which one is the correct reaction pertaining to the lab is limiting reagent analysis, where mass of copper is quantitatively determined or by observations. Through the process of weighing by difference as suggested by the lab manual, anhydrous copper sulfate and iron powder were weighed out. Anhydrous copper sulfate was then dissolved in water on a hot plate and iron was added after the solution of copper sulfate had cooled down to room temperature. The addition of iron took place under the fume hood so as to avoid inhalation of sulfur fumes which were released as a side-product of this reaction. Copper precipitate was then collected by the use of a vacuum filtration setup. The copper precipitate was collected in a sintered glass crucible and mathematical analysis allowed for determination of the correct reaction amongst the two possibilities.
In this lab, iron is being oxidized and this property of iron also allows for the reduction of other types of compounds such as nitro aromatic compounds such as nitrobenzene. This is a key process because nitro aromatic compounds such as nitrobenzene are impurities within the groundwater supply which people are beginning to rely even more nowadays. The nitrobenzene is reduced by iron under anaerobic conditions to aniline which is easier to clear from the groundwater according to the research performed by Abhinash Agrawal1. Materials and Methods:
This lab was carried out using the procedures from the book, An Introduction to Chemical Systems in the Laboratory2 with the following exceptions- * Pan Balance massed out 12.06g of Fe
* Pan Balance massed out 9.01g of CuSO4
* Analytical Balance massed out 2.0095g of Fe
* Analytical Balance massed out 7.0015g of CuSO4
* Addition of 60.0ml of deionized water to anhydrous copper sulfate * Beaker cooled for 10.12 min after heating of CuSO4 for dissolution * Copper precipitate dried for 10min on the vacuum filtration setup * Copper precipitate washed with 15.0ml of water
1Agrawal, Abhinash; Tratnyek, Paul, Reduction of Nitro Aromatic Compounds by Zero-Valent Iron Metal, Environ. Sci. Technol., 1995, 30 (1), pg. 153–160 http://pubs.acs.org/doi/abs/10.1021/es950211h. 2 An Introduction to Chemical Systems in the Laboratory, Hayden-McNeil, University of Illinois, Urbana-Champaign, 2012, Pg. 9-16 * Copper precipitate washed with 15.0, 15.0, 14.0, 15.0ml of acetone Results:
Table 1: Massing of CuSO4, Fe, Crucible on Balances
Balance Type| CuSO4| Fe| Crucible| Crucible + Copper Precipitate| Copper Precipitate| Pan(±0.01g)| 9.01g| 12.06g| -| -| -|
Analytical(No. – 1 West)(±0.0001g)| 7.0015g|...