# Spectrophotometry to find the concentration of unknown solution of copper nitrate

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Purpose: To find the concentration of an unknown solution using spectrophotometry. Hypothesis: I believe the concentration should contain about 13.5-14 cc of our copper nitrate solution diluted in a volumetric flask as its absorbance value is very close to the value obtained with our 15 cc solution. Background Information: Spectrophotometry: Spectrophotometry involves the use of a spectrophotometer. A spectrophotometer is a photometer(a device for measuring light intensity) that can measure intensity as a function of the color, or more specifically, the wavelength of light. There are many kinds of spectrophotometers. Among the most important distinctions used to classify them are the wavelengths they work with, the measurement techniques they use, how they acquire a spectrum, and the sources of intensity variation they are designed to measure. The more direct relation of spectrophotometry to chemistry is that we can manipulate its function in order to calculate the concentration of an unknown solution. This is usually done with the use of the beer lambert equation which is: A=e.C.L Where A=Light absorbance, e=molar absorbtivity, C=concentration of solution and L= the distance our light must pass through our cuvette. Materials: - Copper Powder - Nitric Acid - One 250 cm^3 volumetric flask and ten 100 cm^3 volumetric flasks. - Pipettes. - Beakers. - 1 Weighing Scale - 1 fuming cupboard. - 1 Spectrophotometer. Method to obtain solutions: - Weigh 0.25g of Cu powder in a beaker. - Under fuming cupboard add 1 cm^3 of Nitric Acid in the same beaker. - Pour the Copper Nitrate solution into the 250 cm^3 volumetric flask and dilute it with water until it reaches the line. - Using a pipette pour 5cc, 10cc, 15cc and 20cc of the solution into different volumetric flasks each of 100 cm^3 volume and dilute them until the line mark and