investigation 20
Investigation: 20
How much cobalt is in the soil?
Introduction: By completion of investigation 20, a standard curve of absorbance versus known cobalt (II) nitrate was prepared. The concentration of cobalt (II) ion obtained from a soil sample was determined. Whether or not cobalt nitrate should be added to the soil was determined. If cobalt nitrate needs to be added, then how much will it be required to meet the necessary nutritional needs of the animals was established. In colorimetry, light of a specific wavelength is passed through a solution. A detector measures the amount of light that comes out the other side (transmitted light). The light that is not transmitted is absorbed by the sample. Colored solutions absorb certain wavelengths of visible light to varying extent. The greater the concentration of the sample, the greater the absorbance of light. Beer-Lambert Law states that the amount of light absorbed in colorimetry also depends on the absorbing species, the wavelength of light used, and the thickness of the sample. For this lab, a standard curve is an experimentally measured relationship between concentration and absorbance.
Experimental:
Materials:
0.1 M Co(NO3)2 (aq)
Cuvettes
Unknown cobalt(II) solution
Volume measuring equipment
Device to measure light absorbance
Tissues
The experiment began by calibrating the spectrometer appropriately. By checking if the distilled water (a non-concentrated solution) produced a 0.000 absorbance, made sure that the correct data was collected. A sample solution of the cobalt (II) nitrate was transferred into a test tube and then diluted with distilled water to achieve the desired concentration of the cobalt (II) nitrate. For example, to achieve a 0.5 M cobalt (II) nitrate sample, add 5 mL of the cobalt (II) nitrate sample and dilute it with 5 mL of distilled water in a graduated cylinder. Following that, take the sample and place it in the spectrometer and record its absorbency.
How much cobalt is in the soil?
Introduction: By completion of investigation 20, a standard curve of absorbance versus known cobalt (II) nitrate was prepared. The concentration of cobalt (II) ion obtained from a soil sample was determined. Whether or not cobalt nitrate should be added to the soil was determined. If cobalt nitrate needs to be added, then how much will it be required to meet the necessary nutritional needs of the animals was established. In colorimetry, light of a specific wavelength is passed through a solution. A detector measures the amount of light that comes out the other side (transmitted light). The light that is not transmitted is absorbed by the sample. Colored solutions absorb certain wavelengths of visible light to varying extent. The greater the concentration of the sample, the greater the absorbance of light. Beer-Lambert Law states that the amount of light absorbed in colorimetry also depends on the absorbing species, the wavelength of light used, and the thickness of the sample. For this lab, a standard curve is an experimentally measured relationship between concentration and absorbance.
Experimental:
Materials:
0.1 M Co(NO3)2 (aq)
Cuvettes
Unknown cobalt(II) solution
Volume measuring equipment
Device to measure light absorbance
Tissues
The experiment began by calibrating the spectrometer appropriately. By checking if the distilled water (a non-concentrated solution) produced a 0.000 absorbance, made sure that the correct data was collected. A sample solution of the cobalt (II) nitrate was transferred into a test tube and then diluted with distilled water to achieve the desired concentration of the cobalt (II) nitrate. For example, to achieve a 0.5 M cobalt (II) nitrate sample, add 5 mL of the cobalt (II) nitrate sample and dilute it with 5 mL of distilled water in a graduated cylinder. Following that, take the sample and place it in the spectrometer and record its absorbency.