82164181 Lab Report On Gravimetric Determination Of Nickel PDF

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Running head: LAB REPORT

1

Lab Report on Gravimetric Determination of Nickel Name Institution Affiliation

LAB REPORT

2 Lab Report on Gravimetric Determination of Nickel Abstract

Gravimetric analysis is one of the suitable experimental methods for determining the presence of a substance through the weighing process. The technique was used to determine the percentage of nickel using dimethylglyoxime (DMG) and ammonium hydroxide, which later proved that the samples used contained a small percentage of Ni. The results demonstrated that the method offered a reliable means of determining Ni through weighing. Introduction The gravimetric analysis offers the most suitable analytic method for the determination of a substance through the weighing process (Vogel, 2013). The technique involves the conversion of the element under determination into the stable compound with exact composition followed by accurate determination of the mass. The experiment comprises precipitation, filtration, washing, drying, and weighing of the precipitate (Erdey, 2013). For this experiment, nickel is separated from other ions by precipitation with dimethylglyoxime (DMG) from ammonical solution using the gravimetric method. There are four fundamental types of gravimetric analysis namely physical gravimetry, thermogravimetry, precipitate gravimetry, and electrodeposition (Carmosini, Ghoreshy & Koether, 2014). The experiment focuses on the precipitative gravimetric analysis of nickel. Experimental Procedure The unknown sample of nickel ore was first transferred into the bottle to be weighted then dried before weighing three samples into 400 ml beakers. 20 ml of concentrated nitric acid was added to each sample in the fume hood then warmed gently to the point when there was an

LAB REPORT

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approximately 5ml reduction in volume followed by dilution to approximately 250 ml. A 6 ml of concentrated ammonium hydroxide was then added to the solution then stirred followed by addition of 5 g of solid tartaric acid, which was stirred to form a solution. A solution of 6M ammonium hydroxide was added to the solution to attain a pH. of 8 to 9 followed by filtration, washing, and dilution of the insoluble residue with dilute aqueous ammonia solution. The solution formed was then heated followed by dropwise addition of 20 ml alcoholic DMG solution while stirring before covering with a watch glass for one night for precipitation. The filter flask was then filled with 100 ml water followed by filtration of the precipitate with use of a sintered glass crucible, cooled, and then tested for precipitation with DMG. The precipitate was washed with 5 ml of water then dried in an oven for 30 minutes before being weighed. Results The results and calculations for the percentage of Ni in the ore are as presented in the table below. the weight of the sample by the difference (g) the weight of crucible and precipitate before (g) the weight of crucible and precipitate after drying the weight of (Ni(DMG)2

1.9836

1.9991

1.9824

18.9501

16.0538

18.67

18.7964 15.9542 18.6486 0.1537 0.0996 0.0214 1.57398 1.01205 0.21928 % of Ni in ore % % % Table 1: results and calculations of the percentage of Ni in the ore The formula used in calculating the percentage of Ni in the ore is as follows: The gravimetric factor G.F is given by the formula

LAB REPORT G . F=

4 ¿

¿ ( C8 H 14 O 4 N 4)

=58.693 /288.94

Therefore, the percentage of Ni in the ore is equal to [(weight of precipitate*G.F)/weight of sample]*100% The molar weight of Ni is 58.693, and that of

¿ ( C 8 H 14 O4 N 4)

is 288.94

Conclusion The experiment involved the determination of nickel using the gravimetric analysis, which offered a suitable method for determining the percentage of nickel in the ore. The results show that for every sample used, there was a very small percentage of nickel in the ore. Furthermore, a slow increase in the concentration of ammonia in the solution caused a slight increase in pH forming a denser precipitate. However, it was possible to calculate the weight of the precipitate after collecting and drying the filtrate. Therefore, the gravimetric analysis offered a suitable solution for determining the weight of nickel in the ore.

LAB REPORT

5 Reference

Carmosini, N., Ghoreshy, S., & Koether, M. C. (2014). The gravimetric analysis of nickel using a microwave oven. Journal of chemical education, 74(8), 986. Erdey, L. (2013). Gravimetric Analysis: International Series of Monographs on Analytical Chemistry (Vol. 7). Elsevier. Vogel, A. I. (2013). A Text-Book Of Quantitative Inorganic Analysis-Theory And Practice. Longmans, Green And Co.; London; New York; Toronto....