gatorade
Experiment 3
Spectrophotometric Analysis of Mixtures:
Simultaneous determination of two dyes in solution
Reading: Appendix J
Harris, Section 2.5, Chapter 18, and Section 19.1
Introduction Spectrophotometric determinations based on the Beer-Lambert Law are among the most widely used analytical procedures. These methods involve the measurement of the fraction of incident electromagnetic radiation that is absorbed by a sample. To determine the concentration of a colored species in solution, a cuvet containing the solution is placed in the spectrometer, which consists of a spectrograph and a photometer. The spectrograph produces light of selected wavelengths and is calibrated to indicate the color of the light it produces in terms of wavelength, usually expressed in nanometers. The photometer measures the intensity of the light beam at a given wavelength. The amount of light that is absorbed by the sample can be used to determine the amount of the colored species in solution according to the Beer-Lambert Law.
The absorbance, A, of the solution containing a given metal ion is equal to the molar absorptivity (in liters per mole-cm) times the path length b (in cm) times the concentration c (in moles per liter). This law is known as the Beer-Lambert Law, A = bc. Special sample cuvets are used which have a path length of 1.000 cm. The molar absorptivity depends on the wavelength of the light and is determined by measuring the absorbance of a series of standard solutions of known concentration. Once and b are known, the concentration of an unknown solution can be determined by measuring the absorbance (see Appendix J) and using the Beer-Lambert Law given above.
You will determine the concentrations of both dyesthe Cr3+ and Co2+ simultaneously by a spectrophotometric determination. Since the total absorbance of the solution at a given wavelength is equal to the sum of the absorbances of the individual components, it is possible to analyze the
Spectrophotometric Analysis of Mixtures:
Simultaneous determination of two dyes in solution
Reading: Appendix J
Harris, Section 2.5, Chapter 18, and Section 19.1
Introduction Spectrophotometric determinations based on the Beer-Lambert Law are among the most widely used analytical procedures. These methods involve the measurement of the fraction of incident electromagnetic radiation that is absorbed by a sample. To determine the concentration of a colored species in solution, a cuvet containing the solution is placed in the spectrometer, which consists of a spectrograph and a photometer. The spectrograph produces light of selected wavelengths and is calibrated to indicate the color of the light it produces in terms of wavelength, usually expressed in nanometers. The photometer measures the intensity of the light beam at a given wavelength. The amount of light that is absorbed by the sample can be used to determine the amount of the colored species in solution according to the Beer-Lambert Law.
The absorbance, A, of the solution containing a given metal ion is equal to the molar absorptivity (in liters per mole-cm) times the path length b (in cm) times the concentration c (in moles per liter). This law is known as the Beer-Lambert Law, A = bc. Special sample cuvets are used which have a path length of 1.000 cm. The molar absorptivity depends on the wavelength of the light and is determined by measuring the absorbance of a series of standard solutions of known concentration. Once and b are known, the concentration of an unknown solution can be determined by measuring the absorbance (see Appendix J) and using the Beer-Lambert Law given above.
You will determine the concentrations of both dyesthe Cr3+ and Co2+ simultaneously by a spectrophotometric determination. Since the total absorbance of the solution at a given wavelength is equal to the sum of the absorbances of the individual components, it is possible to analyze the
References: (1 pt): ACS style guidelines (http://library.williams.edu/citing/styles/acs.php) General quality (3 pts): Grammaer, formatting, quality of writing, etc. Lab practice (2 pts)