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Question 5: A set of values for known concentrations of Mn ions were first obtained and...
need help on these Suppose you obtained the following data from two standard solutions of known...
need help on these
Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant HCl concentration. You also prepared four additional standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant NaOH concentration. You then measured the absorbances of these solutions at their respective lamba max wavelengths (AX1 & A2). These absorbances were plotted versus Hin and In molar concentrations respecti vely to produce linear calibration curves with linear equations shown below. AX1...
A student obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI...
A student obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide, CaI 2. She pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. She then pipets 10 mL of this diluted solution into a 50 mL volumetric flask and dilutes to the mark. She analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.0000064 M. Determine the molar concentration...
A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide (CaI...
A chemist obtains 500.0 mL of a solution containing an unknown concentration of calcium iodide (CaI 2). She pipets 25 mL of this solution into a 100 mL volumetric flask and dilutes to the mark. Shethen pipets 10 mL of this diluted solution into a 25 mL volumetric flask and dilutes to the mark. She analyzes some of the solution from the final volumetric flask and finds that the iodide ion concentration is 0.00000446 M. (in solution, calcium iodide breaks...
5. The following data were obtained when Bio 106 students created solutions of the following concentrations...
5. The following data were obtained when Bio 106 students created solutions of the following concentrations (column 1), These students then placed three different samples of each concentration in a spectrophotometer and measured the absorbance. The following data table was created by these students. Create a standard curve from the data in the following table. Be sure to calculate the average absorbance for each concentration (round to two decimal places). After you have created the table, answer the following questions....
1. A series of solutions, containing cobalt (I1) chloride were prepared with concentrations shown below. Using...
1. A series of solutions, containing cobalt (I1) chloride were prepared with concentrations shown below. Using PhET Simulation find the absorbance values corresponding to each solution at the preset value of wave length 549 nm, using 1 cm wide cuvette. Concentration of Co (II), mM 121 98.0 60.0 24.0 15.0 Absorbance Plot a calibration line Absorbance versus Concentration. From the graph determine the specific absorptivity. 2. Using the data you obtained from the graph in the previous problem determine the...
Mn was used as an internal standard for measuring Fe by atomic absorption. A standard mixture...
Mn was used as an internal standard for measuring Fe by atomic absorption. A standard mixture containing 2.00 Hg/mL Mn and 2.50 Hg/mL Fe gave a quotient (Fe signal/Mn signal) 1.05/1.00. A solution was prepared by mixing 10.00 mL of unknown Fe solution with 10.00 mL of standard containing 8.24 ug/mL Mn, and diluting to 50.00 mL; the measured absorbance signal at the Fe wavelength was 0.197, and at the Mn wavelength the absorbance was 0.116. Calculate the molar concentration...
question one question two Aspirin lab (10 points) 5. a) Spectroscopy is being used to determine...
question one
question two
Aspirin lab (10 points) 5. a) Spectroscopy is being used to determine the concentration of aspirin in an unknown sample. The absorbance spectrum of the highest concentration standard [Fe3+, SA) prepared is given below. What wavelength should be used to create the calibration curve for the experiment? Explain your reasoning. 0.14 Absorbance 0.02 250 300 450 500 350 400 Wavelength (nm) Wavelength Explain your reason briefly. b) In this experiment an aspirin tablet was placed in...
Imported ceramic bowls are analyzed for toxic heavy metals such as cadmium since these metals can...
Imported ceramic bowls are analyzed for toxic heavy metals such as cadmium since these metals can be leached from the ceramic by the food in contact with it. The amount of cadmium that can be leached from the bowl is determined by adding an acetic acid solution to the bowl for a 24 hour period, after which the cadmium concentration in the acidic leaching solution is determined. In one experiment, the cadmium concentration in an acidic leaching solution was analyzed...
PRE-LAB (5): EXPERIMENT #7, Redox and Spectrophotometric Determina 7, Redox and Spectrophotometric Determination of Manganese in...
PRE-LAB (5): EXPERIMENT #7, Redox and Spectrophotometric Determina 7, Redox and Spectrophotometric Determination of Manganese in order to analyze for manganese by photometry, Mn? in the sample is converted to deep purple MnO.. What reagent is used to bring about this oxidation 4420 2. (1) Write and balance the redox reaction for the oxidation of Mn(II) to Mn(VII). How many electrons are involved? 3. (1/2) Sometimes you get a brown precipitate during the oxidation step in this experiment. What is...
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Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
You prepared four standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant HCl concentration. You also prepared four additional standard solutions by serial dilutions that contained decreasing concentrations of bromocresol green, but constant NaOH concentration. You then measured the absorbances of these solutions at their respective lamba max wavelengths (AX1 & A2). These absorbances were plotted versus Hin and In molar concentrations respecti vely to produce linear calibration curves with linear equations shown below. AX1...
5. The following data were obtained when Bio 106 students created solutions of the following concentrations (column 1), These students then placed three different samples of each concentration in a spectrophotometer and measured the absorbance. The following data table was created by these students. Create a standard curve from the data in the following table. Be sure to calculate the average absorbance for each concentration (round to two decimal places). After you have created the table, answer the following questions....
1. A series of solutions, containing cobalt (I1) chloride were prepared with concentrations shown below. Using PhET Simulation find the absorbance values corresponding to each solution at the preset value of wave length 549 nm, using 1 cm wide cuvette. Concentration of Co (II), mM 121 98.0 60.0 24.0 15.0 Absorbance Plot a calibration line Absorbance versus Concentration. From the graph determine the specific absorptivity. 2. Using the data you obtained from the graph in the previous problem determine the...
Mn was used as an internal standard for measuring Fe by atomic absorption. A standard mixture containing 2.00 Hg/mL Mn and 2.50 Hg/mL Fe gave a quotient (Fe signal/Mn signal) 1.05/1.00. A solution was prepared by mixing 10.00 mL of unknown Fe solution with 10.00 mL of standard containing 8.24 ug/mL Mn, and diluting to 50.00 mL; the measured absorbance signal at the Fe wavelength was 0.197, and at the Mn wavelength the absorbance was 0.116. Calculate the molar concentration...
question one
question two
Aspirin lab (10 points) 5. a) Spectroscopy is being used to determine the concentration of aspirin in an unknown sample. The absorbance spectrum of the highest concentration standard [Fe3+, SA) prepared is given below. What wavelength should be used to create the calibration curve for the experiment? Explain your reasoning. 0.14 Absorbance 0.02 250 300 450 500 350 400 Wavelength (nm) Wavelength Explain your reason briefly. b) In this experiment an aspirin tablet was placed in...
Imported ceramic bowls are analyzed for toxic heavy metals such as cadmium since these metals can be leached from the ceramic by the food in contact with it. The amount of cadmium that can be leached from the bowl is determined by adding an acetic acid solution to the bowl for a 24 hour period, after which the cadmium concentration in the acidic leaching solution is determined. In one experiment, the cadmium concentration in an acidic leaching solution was analyzed...
PRE-LAB (5): EXPERIMENT #7, Redox and Spectrophotometric Determina 7, Redox and Spectrophotometric Determination of Manganese in order to analyze for manganese by photometry, Mn? in the sample is converted to deep purple MnO.. What reagent is used to bring about this oxidation 4420 2. (1) Write and balance the redox reaction for the oxidation of Mn(II) to Mn(VII). How many electrons are involved? 3. (1/2) Sometimes you get a brown precipitate during the oxidation step in this experiment. What is...
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