Lab Report 2: Quantitative Analysis
Finding the Percentage Composition of Nickel in an Unknown Compound Introduction:
This section of lab was about using analytical chemistry and learning how to identify the amount of nickel in an unknown substance. The purpose was to use gravimetric analysis to quantitatively separate and weigh insoluble reaction products as well as utilize the mole method to compute the amount and percentage of nickel in an unknown nickel sample. The chemical reaction that took place involved the reaction between DMG (Dimethylglyoxime, C4H8N202) and the Hydroxide ion (OH-) to produce DMG- (C4H7N202-) and Water (H20). Then there was a reaction between DMG- (C4H7N202-) and the Nickel ion (Ni2+) to produce Ni(DMG)2 [Ni(C4H7N202)]. This lab could be applied to the real world in the analytical chemistry industry. Some analytical chemists may work in laboratories for a pharmaceutical company developing and maintaining standards to ensure consistency in the production of medicine. Procedure:
First a weigh boat was weighed as precisely as possible, and then the weigh boat was weighed with a filter paper placed inside it. Next, about 0.2 grams of the unknown nickel compound C was weighed in a clean beaker. The mass of the unknown was determined as precisely as possible. The sample was put in about 20 mL of deionized water and stirred together until the nickel compound was completely dissolved. Then, about 25 mL of dimethylglyoxime (DMG) solution was obtained in a clean graduated cylinder. Before mixing the two solutions together, the nickel compound was placed under the fume hood and four drops of concentrated ammonium hydroxide solution (NH4OH) was added to it. This ensured that all of the nickel ion in the solution was precipitated as nickel dimethylglyoxime (Ni(DMG)2) when the DMG was added. The Buchner funnel filtration apparatus was assembled and the filter paper was wet with a small amount of deionized water from a wash bottle. Aspiration...
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