To minimize the uncertainty in the measured concentration of an unknown using a visible spectrophotometer, the...
To minimize the uncertainty in the measured concentration of an unknown using a visible spectrophotometer, the analyst should
a. Use a wavelength exhibiting high absorptivity.
b. Select a wavelength where only the analyte responds.
c. Adjust the absorbance of the unknown so that it is close to the mean absorbances of the standards used to develop the calibration curve.
d. All of the above.
Homework Answers
The answer is (d) All the above.
All these are to be taken care of while measuring the unknown.
Add Answer to:
To minimize the uncertainty in the measured concentration of an
unknown using a visible spectrophotometer, the...
1. Use the following data to construct a calibration curve and determine the concentration of unknown...
1. Use the following data to construct a calibration curve and determine the concentration of unknown as given. What is the molar absorptivity of the analyte? The compound solutions were measured in a 0.5 cm path length quartz cuvette. solution [X] (M) Absorbance At 254 nm Standard 1 Standard 2 Standard 3 Standard 4 Standard 5 Sample 0.03584 0.05719 0.1289 0.2305 0.3161 ??? 0.097 0.169 0.365 0.682 0.997 0.719
A- B- C- In Part C students will make the standard solutions to find a calibration...
A-
B-
C-
In Part C students will make the standard solutions to find a calibration curve. The experiment's Standard 1 consists of 0.13 M CuSO4. What will be the concentration of Standard 2 if it is prepared by combining 10.0 mL of Standard 1 with 10.0 mL deionized water? How should you set up the spectrophotometer? Make sure your cuvettes are clean and dry before use. Turn it on as soon as you can so it can warm up....
A student prepares a caffeine standard solution that has a concentration of 1858 ppm. To prepare...
A student prepares a caffeine standard solution that has a concentration of 1858 ppm. To prepare a calibration curve, the student pipets various volumes of the standard solution into 50.0 mL volumetric flasks and dilutes to the fill line with water. The absorbance of each solution is measured in a 1.00 cm cuvette using the spectrophotometer and is shown in the table below. Calculate the concentration of each solution and create a calibration curve using the absorbance data provided. Based...
An aspirin solution of unknown concentration was studied using ultraviolet spectroscopy. This solution had a percent...
An aspirin solution of unknown concentration was studied using ultraviolet spectroscopy. This solution had a percent transmittance of 37.3 when measured at 273 nm in a 1.000-cm cell. Aspirin is known to have a molar absorptivity of 741 M-1cm-1 at this wavelength. a. Calculate the absorbance of this solution b. What is the concentration of aspirin in this solution? c. What would be the absorbance of a solution prepared by taking 10.00mL of this solution and diluting to 100.00mL in...
Page 10 Beer's Law Akuch Pyrs to shes your werk Show your work, Aplications Attach Peyes...
Page 10 Beer's Law Akuch Pyrs to shes your werk Show your work, Aplications Attach Peyes 27, what is the value of absorbance that corresponds to 35.0 %T? 28. Molar absorpt ivity is the absorptivity when concentration is in units of molarity and the gth is in centimeters. If a 1.53 x 10 M solution has an absorbance of 0.426 in a 1.00 em cell when measured at a wavelength of 254 nm, what is the molar absorptivity of the...
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...
1. Determining the Wavelength of Maximum Absorption: 2. Determining the concentration of an Unknown Solution Volume...
1. Determining the Wavelength of Maximum Absorption: 2. Determining the concentration of an Unknown Solution Volume of Stock Concentration of Soln #1 T2.001.xlon #2 5.00 2.5x loin . . x ^ 10.00 Soxom A=493.6 mm Rad y o sxlom Recorded Absorbance 0.212 0.528 0.947 1453 #4 Calibration Curve Slope of Least Squares Best Fit Line (molar abspoptivity, E) Equation for Least squares best fit line: A-42. Ubxk 2916xlor 6-01482 0.9652 Correlation Factor (R) for Least Squares Best Fit Line 3....
Beer’s Law Objective : We will explore an application of absorption spectroscopy using calibration curves and...
Beer’s Law Objective : We will explore an application of absorption spectroscopy using calibration curves and Beer’s Law. Use the “LAB : HOW TO…” link from the class website if you need help with how to use balance, Bunsen burner… and such. Introduction: You may write this information in your lab notebook for your own reference. It can’t be cut and pasted. Different solutions have different spectral properties. In this portion of the experiment those properties will be utilized to...
Part C. Quantitative Spectroscopy Wavelength(A) Absorbance Amax-10 Amax 10 Wavelength used for Analysis in Part C:...
Part C. Quantitative Spectroscopy Wavelength(A) Absorbance Amax-10 Amax 10 Wavelength used for Analysis in Part C: Solution Concentration Absorbance % Transmittance Standard 1 Standard 2 Standard 3 Standard 4 Unknown 0.20 M Show an example calculation obtaining the molarity of the standards. a. Copper Standard 2: Obtain additional 0.20 M CuSO4 solution from the tray. Pipet 10 mL of 0.20 M CuSO4 solution into a 50 mL Erlenmeyer flask. Pipet 10 mL of DI water into the same tube and...
Part 2. UV-Visible Spectroscopy Cut2 concentration Absorbance (mol/L) 0.0010 0.053 0.0025 0.128 0.0050 0.251 0.0075 0.378...
Part 2. UV-Visible Spectroscopy Cut2 concentration Absorbance (mol/L) 0.0010 0.053 0.0025 0.128 0.0050 0.251 0.0075 0.378 0.0100 0.510 Diluted unknown, Trial 1 0.079 For your lab notebook: C. Sketch how you could make each of the the 5 standards for Part 2 from a 0.100 mol/L Cu2+ stock solution, 1.25 mol/L NH3 solution, and Dl water. The procedure is referenced in step 2b. Assume you would use 10-mL volumetric flasks to make the solutions. d. Sketch also how you would...
1. Use the following data to construct a calibration curve and determine the concentration of unknown as given. What is the molar absorptivity of the analyte? The compound solutions were measured in a 0.5 cm path length quartz cuvette. solution [X] (M) Absorbance At 254 nm Standard 1 Standard 2 Standard 3 Standard 4 Standard 5 Sample 0.03584 0.05719 0.1289 0.2305 0.3161 ??? 0.097 0.169 0.365 0.682 0.997 0.719
A-
B-
C-
In Part C students will make the standard solutions to find a calibration curve. The experiment's Standard 1 consists of 0.13 M CuSO4. What will be the concentration of Standard 2 if it is prepared by combining 10.0 mL of Standard 1 with 10.0 mL deionized water? How should you set up the spectrophotometer? Make sure your cuvettes are clean and dry before use. Turn it on as soon as you can so it can warm up....
Page 10 Beer's Law Akuch Pyrs to shes your werk Show your work, Aplications Attach Peyes 27, what is the value of absorbance that corresponds to 35.0 %T? 28. Molar absorpt ivity is the absorptivity when concentration is in units of molarity and the gth is in centimeters. If a 1.53 x 10 M solution has an absorbance of 0.426 in a 1.00 em cell when measured at a wavelength of 254 nm, what is the molar absorptivity of the...
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...
1. Determining the Wavelength of Maximum Absorption: 2. Determining the concentration of an Unknown Solution Volume of Stock Concentration of Soln #1 T2.001.xlon #2 5.00 2.5x loin . . x ^ 10.00 Soxom A=493.6 mm Rad y o sxlom Recorded Absorbance 0.212 0.528 0.947 1453 #4 Calibration Curve Slope of Least Squares Best Fit Line (molar abspoptivity, E) Equation for Least squares best fit line: A-42. Ubxk 2916xlor 6-01482 0.9652 Correlation Factor (R) for Least Squares Best Fit Line 3....
Part C. Quantitative Spectroscopy Wavelength(A) Absorbance Amax-10 Amax 10 Wavelength used for Analysis in Part C: Solution Concentration Absorbance % Transmittance Standard 1 Standard 2 Standard 3 Standard 4 Unknown 0.20 M Show an example calculation obtaining the molarity of the standards. a. Copper Standard 2: Obtain additional 0.20 M CuSO4 solution from the tray. Pipet 10 mL of 0.20 M CuSO4 solution into a 50 mL Erlenmeyer flask. Pipet 10 mL of DI water into the same tube and...
Part 2. UV-Visible Spectroscopy Cut2 concentration Absorbance (mol/L) 0.0010 0.053 0.0025 0.128 0.0050 0.251 0.0075 0.378 0.0100 0.510 Diluted unknown, Trial 1 0.079 For your lab notebook: C. Sketch how you could make each of the the 5 standards for Part 2 from a 0.100 mol/L Cu2+ stock solution, 1.25 mol/L NH3 solution, and Dl water. The procedure is referenced in step 2b. Assume you would use 10-mL volumetric flasks to make the solutions. d. Sketch also how you would...
Most questions answered within 3 hours.
-
You working as a clinical engineer dealing with
autoclaves, xrays and life care machines, in what...
asked 57 seconds from now -
Explain in detail (not just enumerate) each of Koch’s
postulates to determine the etiology of a...
asked 11 minutes ago -
Assume ABC Company has asked you to not only prepare their 2017
year-end Balance Sheet but...
asked 8 minutes ago -
You have just had a new set of tires put on your car, and now
the...
asked 14 minutes ago -
Please answer ASAP 2) Choose a point at random from the unit
square [0, 1] ×...
asked 28 minutes ago -
Draw the Lewis structures and determine which of these
molecules has a central atom that unavoidably...
asked 29 minutes ago -
Do we typically carry antibodies against the RH antigen in our
blood plasma?
asked 31 minutes ago -
What are the differences between an antibiotic, a semisynthetic,
and a synthetic as types of antimicrobials?
asked 27 minutes ago -
One mole of oxygen gas is at a pressure of 5.90 atm and a
temperature of...
asked 35 minutes ago -
The primary side of a transformer has 935 turns and is connected
to 118 Volts A/C....
asked 33 minutes ago -
This must be done in Java and it must contain a public static
void (string []args)...
asked 37 minutes ago -
An economy has a Cobb–Douglas production function:
Y=Kα(LE)1−αY=Kα(LE)1−α
The economy has a capital share of 0.30,...
asked 51 minutes ago