I'm confused please help. If you are given an absorbance and wavelength graph, how do you...
I'm confused please help.
If you are given an absorbance and wavelength graph, how do you find molar absorptivity? Is molar absorptivity from the graph itself or do you need to find this online to calculate concentration? And from the absorbance and wavelength graph, what is the use of knowing lambda max?
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I'm confused please help.
If you are given an absorbance and wavelength graph, how do you...
I'm a little lost and how to do the calculations. Please help? Wavelength of maximum absorbance,...
I'm a little lost and how to do the calculations. Please
help?
Wavelength of maximum absorbance, lambda_min, determined from your prelab oratory graph of the data in Table 2 525 nm Concentration of Erythrosine B standard solution Diluted Solution Diluted Unknown Absorbance Known Solutions Molarity of standard solution (I) Molarity of stock solution (S) Calibration curve values
In spectrophotometry, the Beer-Lambert law relates the absorbance of a sample at a given wavelength to...
In spectrophotometry, the Beer-Lambert law relates the absorbance of a sample at a given wavelength to concentration by the following formula. a = abc You synthesize a new dve with molar absorptivity & = 2.9081 x 10+ 0.0002 x 10 M cm and use a cuvet with pathlength of 1,02 +0.03 cm. The absorbance was determined to be 0.7341 0.0009 Calculate the concentration in molarity with its associated uncertainty. (6pts) If you wanted to improve the uncertainty of your final...
When using a spectrometer to measure the absorbance as a function of concentration, why do we...
When using a spectrometer to measure the absorbance as a function of concentration, why do we have to plot our calibration curve at the maximum wavelength (lambda max)? I know it's to get the highest point of absorbance and therefore ensure high sensitivity, but how does it affect my answers on the calibration curve? what if I didn't use lambda max?
a) If a compound has the wavelength of maximum absorbance of 600 nm, what would happen...
a) If a compound has the wavelength of maximum absorbance of 600 nm, what would happen if all of the samples were measured at a slightly higher wavelength (i.e. 620 nm)? b) When plotting data of concentration vs. absorption of the compound, will the change in wavelength affect the R^2 value of the graph? why or why not? c) Will the change in wavelength affect the molar absorptivity calculated from the graph? why or why not?
Spectrophotometry help!? Would measuring the absorbance of the standard solutions used to prepare a calibration curve...
Spectrophotometry help!? Would measuring the absorbance of the standard solutions used to prepare a calibration curve and the unknown sample using a wavelength 10 nm higher or lower than lambda max provide an accurate concentration value for the unknown? Explain. If in an experiment, the pathlength of the light is 1 cm, and the concentration unit of the standard solutions is reported as mM, what would the units of the molar extinction coefficient, ε, be?
need help b) Potassium dichromate K2Cr207 absorbs light at a wavelength of 345nm. A solution of...
need help
b) Potassium dichromate K2Cr207 absorbs light at a wavelength of 345nm. A solution of potassium dichromate with chromium concentration of 40.0mg/L gave an absorbance of 0.412 when measured using a 1cm cell. What is the molar absorptivity (give units) of potassium dichromate K2Cr207 at this wavelength? (hint: need to convert concentration to moles/L)
Question 8 Status: Tries remaining: 21 Points possible: 1.00 Suppose you measure the absorbance of a...
Question 8 Status: Tries remaining: 21 Points possible: 1.00 Suppose you measure the absorbance of a yellow dye solution in a 1.00 cm cuvette. cm what is The absorbance of the solution at 427 nm is 0.46. If the molar absorptivity of yellow dye at 427 nm is 27400 M the concentration of the solution? Answer: Question 9 Status: Tries remaining: 2 Points possible: 1.00 If you plot the absorbance measurements of solutions vs. their concentrations, what is the slope...
Please help I am completely confused, I included the 2 graphs needed for this post lab....
Please help I am completely confused, I included the 2
graphs needed for this post lab. Thank you!
Postlab Assignments . (a) Using your own standard curve, the line equation you generated and Beer's law equation Equation 1) calculate the molar absorpivity (e) of blue dye. For all your measurem cuvette used is 1.00 cm. Use this as the value of b in Equation 1 ents, the size of (b) Using Beer's law equation again, what does a high value...
Name: Determination of Solution Concentration by Spectrophotometry PRELAB QUESTIONS 1. A student measures the absorbance of...
Name: Determination of Solution Concentration by Spectrophotometry PRELAB QUESTIONS 1. A student measures the absorbance of an unknown after placing a sample in a cuvette which contained some water. How will this affect the concentration he reports? 2. Explain why it is all right to leave water in the volumetric flask before you put in the 10.00 mL of your unknown. 3. A 1.3 x 10-M solution of an unknown substance has an absorbance of 0.345 at its max. a)...
help! i'm not sure how to go about this. ABSORBANCE PLOT DATA Please attach a copy...
help! i'm not sure how to go about this.
ABSORBANCE PLOT DATA Please attach a copy of your print out from the spectrophotometer, or indicate that it is attached to your lab partners report and give their name. ron A= emll Analytical wavelength used (=(A-b)lum CALIBRATION CURVE DATA Concentration of Stock Solution: 5.00 X 10 M Door Test Tube Volume Final Volume Final Stock Soln. Solution Concentration 1 2.00 10.0 Absorbance Trial 1 Absorbance Trial 2 2. 4.00 10.0 3...
I'm a little lost and how to do the calculations. Please
help?
Wavelength of maximum absorbance, lambda_min, determined from your prelab oratory graph of the data in Table 2 525 nm Concentration of Erythrosine B standard solution Diluted Solution Diluted Unknown Absorbance Known Solutions Molarity of standard solution (I) Molarity of stock solution (S) Calibration curve values
In spectrophotometry, the Beer-Lambert law relates the absorbance of a sample at a given wavelength to concentration by the following formula. a = abc You synthesize a new dve with molar absorptivity & = 2.9081 x 10+ 0.0002 x 10 M cm and use a cuvet with pathlength of 1,02 +0.03 cm. The absorbance was determined to be 0.7341 0.0009 Calculate the concentration in molarity with its associated uncertainty. (6pts) If you wanted to improve the uncertainty of your final...
need help
b) Potassium dichromate K2Cr207 absorbs light at a wavelength of 345nm. A solution of potassium dichromate with chromium concentration of 40.0mg/L gave an absorbance of 0.412 when measured using a 1cm cell. What is the molar absorptivity (give units) of potassium dichromate K2Cr207 at this wavelength? (hint: need to convert concentration to moles/L)
Question 8 Status: Tries remaining: 21 Points possible: 1.00 Suppose you measure the absorbance of a yellow dye solution in a 1.00 cm cuvette. cm what is The absorbance of the solution at 427 nm is 0.46. If the molar absorptivity of yellow dye at 427 nm is 27400 M the concentration of the solution? Answer: Question 9 Status: Tries remaining: 2 Points possible: 1.00 If you plot the absorbance measurements of solutions vs. their concentrations, what is the slope...
Please help I am completely confused, I included the 2
graphs needed for this post lab. Thank you!
Postlab Assignments . (a) Using your own standard curve, the line equation you generated and Beer's law equation Equation 1) calculate the molar absorpivity (e) of blue dye. For all your measurem cuvette used is 1.00 cm. Use this as the value of b in Equation 1 ents, the size of (b) Using Beer's law equation again, what does a high value...
Name: Determination of Solution Concentration by Spectrophotometry PRELAB QUESTIONS 1. A student measures the absorbance of an unknown after placing a sample in a cuvette which contained some water. How will this affect the concentration he reports? 2. Explain why it is all right to leave water in the volumetric flask before you put in the 10.00 mL of your unknown. 3. A 1.3 x 10-M solution of an unknown substance has an absorbance of 0.345 at its max. a)...
help! i'm not sure how to go about this.
ABSORBANCE PLOT DATA Please attach a copy of your print out from the spectrophotometer, or indicate that it is attached to your lab partners report and give their name. ron A= emll Analytical wavelength used (=(A-b)lum CALIBRATION CURVE DATA Concentration of Stock Solution: 5.00 X 10 M Door Test Tube Volume Final Volume Final Stock Soln. Solution Concentration 1 2.00 10.0 Absorbance Trial 1 Absorbance Trial 2 2. 4.00 10.0 3...
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