% Copper In An Ore

Quantitative Analysis: % Copper in an Ore

May 3, 2006

Abstract: In this experiment we were given an unknown sample of ore. Using the spectrophotometric analysis and the electrogravimetric analysis, we found the unknown percentage of copper in the unknown sample of ore was to be 17.6% by mass.

Introduction: Chemical analysis takes place under two different scenarios. In one case, you need to find out the chemical identity of some material. The first kind of analysis, in which the chemical nature of a sample is determined in the lab0 or in the field, is called qualitative analysis. In the second type of analysis, the analyst, in which amounts of specific substances are measured, is quantitative analysis. As in this experiment is to determine the mass percentage of copper in a copper ore sample, using a variety of analytical methods.

Methods:

Electrolytic Analysis of Cu in an Ore

In order to find the electrolytic analysis of Cu in an Ore, we precisely weighed out a 3.4585 g of the unknown (#75) ore sample into a 250 ml beaker. We then added 25 ml of de-ionized water, 2 ml of concentrated sulfuric acid, and 1 ml of concentrated nitric acid. We then heated the mixture over a hot plate until no more dissolving occurs. We then cooled the solution and diluted it with de-ionized water to a 100 ml volume. We then used the, Eberbach Corp #6, electrolysis machine (serial # 749864) to stir the electrodes in the beaker of solution for approximately 30 minutes at 3 volts and 1.4 amperes. We then added de-ionized water to bring the volume of solution up and continued the process. We repeated the adding of de-ionized water and the stirring of solution until no more blue color remained in the solution and no further copper plating was observed.

Spectrophotometric Analysis of Cu in an Ore

In order to find the spectrophotometric analysis of Cu in an Ore, we made a 0.0500 M Cu2+ solution by pouring 35 ml of the stock 0.100 M Cu2+ solution and transferring 25.00 ml of the solution to a flask and adding de-ionized water to the calibration line on the neck of the flask and swirling vigorously for 10 minutes. We then confirmed that are blank cuvettes read 0 on the Genesys spectrophotometer . We then measured the 0.500 M Cu2+ absorbance of wave length every 25 nm until reaching 950 nm. We then found our wavelength at which A is a maximum and repeated measuring every 5 nm.

We then diluted our solution further using a pipette adding 20 ml, 10 ml, and 5 ml to three separate 25 ml volumetric flask and diluted to the calibration line and swirled vigorously. We then measured the absorbance of wavelength

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