The aim of this experiment was to find out how much cobalt is in the soil being tested. Use of colorimetry technique of colorimetry (spectroscopy) will determine the concentration of the cobalt (II) ion, Co 2+, in an unknown solution got from different soil samples. It is possible to determine the relationship between concentrated and light absorbance in the soil using the colorimeter. In colorimetry, a light of a stated wavelength passes through a solution, and a detector measures light amount that comes out the other side. The amount of light absorbed shows the absorbent level of the solution.
One will need to prepare a solution of cobalt (II) nitrate before commencing with the experiment. This can be achieved by reacting the cobalt (II) salt with nitric acid and different water levels for the desired result. Co(NO3)2.6H2O. This is a deliquescent salt known to be soluble in water and other solvents that are polar. After presenting the solution to the lab, a colorimeter is used to measure the amount of concentration in the soil. The absorbance and transmittance levels will determine the concentration of the metallic element in the soil. The greater the level of absorbance, the higher the concentration of the metal in the soil sample. When measuring the absorbent levels of different elements, it is necessary to use only the wavelength. This is because light transmitted through an opaque object is similar to the light reflected from the eyes. There are some wavelengths of visible light absorbed by these objects.
Various factors determine the light absorbed by a solution; absorbing species, thickness of the sample and wavelength of used light. It is the beer-lambert law that will determine the amount of cobalt levels in the soil. It combines a solution’s absorbent levels, the level of concentration of the sample, the thickness of the solution and a constant to determine the concentration levels. In the experiment, to gain accuracy in the result, the absorbent level of the solution has to be directly proportional to the concentration.