How would you demonstrate accuracy of an analytical method? a)Run a sample with a known concentration...
How would you demonstrate accuracy of an analytical method?
a)Run a sample with a known concentration of analyte and see if the concentration you determine matched the known value
b)Determine LOD for the method – it must be below 100 ng/ml for analyte dissolved in reagent (ultrapure) water
c)Use least-squares method to determine the slope of the calibration curve (in the slope is less than 10, the method is inaccurate)
Homework Answers
Option b-determine LOD for the method --t must be below 100mg/ml for analyse dissolved in reagent water .
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How would you demonstrate accuracy of an analytical method?
a)Run a sample with a known concentration...
You are asked to determine the amount of salicylic acid expressed in molar concentration ([Sal]) in...
You are asked to determine the amount of salicylic acid expressed in molar concentration ([Sal]) in an unknown sample of aspirin. You decide to use an UV-Vis spectrometer absorption method and run the following standards of Sal to construct a calibration curve. Use the Excel program and prepare the plot Absorbance vs. [Sal]. Determine the equation for the best least squares fit (calibration equation). Determine the concentration of salicylic acid in mol/L in your unknown sample of aspirin. [Sal], mol/L...
Problem 4 (10 Points). You collect a sample of wastewater and run a BOD test. To...
Problem 4 (10 Points). You collect a sample of wastewater and run a BOD test. To run this test, you mix 25 mL of the wastewater sample with clean (unseeded) dilution water to bring the total volume in the bottle to 300 ml, After measuring the initial dissolved oxygen concentration, you cap the BOD bottle and monitor the dissolved oxygen concentration of the diluted sample in the BOD bottle as a function of time (see Figure below). Previous tests have...
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....
The table filled is the lab run. Please can you use the three informations provided above...
The table filled is the lab run.
Please can you use the three informations provided above to answer
the empty table
Take Density of vinegar = 1.005g/mol
concentration of NaOH = 0.1205M
Experiment #7. Titration of Vinegar Goals 1. To determine the mass percent of acetic acid in a solution via titration. 2. To master the technique of titration. Introduction Vinegar is a common household item that is found in a number of products from salad dressing to cleaners. Vinegar...
answer (2) 2. Suppose that you used a known concentration (0.8442 M) of Ca(OH)2 to determine...
answer (2)
2. Suppose that you used a known concentration (0.8442 M) of Ca(OH)2 to determine the concentration of an unknown HBr solution. If it takes 12.88 mL of the Ca(OH)2 solution to titrate 15.00 mL of the unknown HBr solution, what is the molarity of the HBr? 1. A solid diprotic weak acid, H2A (molecular weight = 128.9 g/mol) is used to standardize a KOH solution. When 0.4228 g of the acid is dissolved in 40.0 mL of water...
using microsoft excel, plot the absorbance (y-axis) vs. the concentration of each FAS standard standard (in g/ml) Use the method of least squares (linear regression) to determine the slope, intercept,...
using microsoft excel, plot the absorbance (y-axis) vs. the concentration of each FAS standard standard (in g/ml) Use the method of least squares (linear regression) to determine the slope, intercept, and correlation coefficient. Compare your slope with the literature value of 11,100 liter*mol^-1*cm^-1. You will have to convert your slope to have the same units as the literature value. Please do this unit conversion in your notebook. (FW FAS=392.13) Absorbance was read at 508 nm in a 1 cm curvette....
2. Assume you start with a 2.00 g sample of copper (II) nitrate. a. How many...
2. Assume you start with a 2.00 g sample of copper (II) nitrate. a. How many moles of copper (II) nitrate do you start with? b. Your sample will undergo multiple steps, each of which has the potential for loss of product. Assuming a percent yield of only 65.0 %, how many moles of copper (II) sulfate would you expect to produce? c. If the product is now dissolved in water inside of a 50-mL volumetric flask (as in the...
I am stuck on how to find concentration for standards and unknowns. Any kind of help would be appreciated. The correct...
I am stuck on how to find concentration for standards and
unknowns. Any kind of help would be appreciated.
The corrected absorbance is = Blank - absorbance
1. Prepare the BCA working reagent. Use a graduated cylinder and add 30 ml of the BCA reagent into a 50 ml Erlenmeyer flask. Use the appropriate micropipette to add 600 uL of the CuSO4 solution into the flask and mix by swirling the flask. Record the exact mass of albumin and the...
Compare the floating of hydrometer in a diet cola with a regular soft drink How could...
Compare the floating of hydrometer in a diet cola with a regular
soft drink
How could the hydrometer be modified to increase
A large tub of ice and water holds cans of both regular and
diet pop. Some cans some don What can you surmise regarding their
content?
POST-LAB Questions 1. Compare the floating of a hydrometer in a diet cola with a regular soft drink. How could the hydrometer be modified to increase accuracy? A large tub of ice...
CHEMISTRY HELP NEEDED!! How do I do this problem? can someone show me a step-by-step tutorial?...
CHEMISTRY HELP NEEDED!! How do I do this problem? can someone
show me a step-by-step tutorial? I will vote and answer your
response, thanks in advance!
Standard Addition Method Problem Often when doing analytical work, we need to spike our sample because of matrix effects that impact our measurements. This involves making a series of solutions that include increasing amounts of a standard solution of known concentration along with a set amount of the unknown solution, diluting to a mark...
Problem 4 (10 Points). You collect a sample of wastewater and run a BOD test. To run this test, you mix 25 mL of the wastewater sample with clean (unseeded) dilution water to bring the total volume in the bottle to 300 ml, After measuring the initial dissolved oxygen concentration, you cap the BOD bottle and monitor the dissolved oxygen concentration of the diluted sample in the BOD bottle as a function of time (see Figure below). Previous tests have...
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....
The table filled is the lab run.
Please can you use the three informations provided above to answer
the empty table
Take Density of vinegar = 1.005g/mol
concentration of NaOH = 0.1205M
Experiment #7. Titration of Vinegar Goals 1. To determine the mass percent of acetic acid in a solution via titration. 2. To master the technique of titration. Introduction Vinegar is a common household item that is found in a number of products from salad dressing to cleaners. Vinegar...
answer (2)
2. Suppose that you used a known concentration (0.8442 M) of Ca(OH)2 to determine the concentration of an unknown HBr solution. If it takes 12.88 mL of the Ca(OH)2 solution to titrate 15.00 mL of the unknown HBr solution, what is the molarity of the HBr? 1. A solid diprotic weak acid, H2A (molecular weight = 128.9 g/mol) is used to standardize a KOH solution. When 0.4228 g of the acid is dissolved in 40.0 mL of water...
I am stuck on how to find concentration for standards and
unknowns. Any kind of help would be appreciated.
The corrected absorbance is = Blank - absorbance
1. Prepare the BCA working reagent. Use a graduated cylinder and add 30 ml of the BCA reagent into a 50 ml Erlenmeyer flask. Use the appropriate micropipette to add 600 uL of the CuSO4 solution into the flask and mix by swirling the flask. Record the exact mass of albumin and the...
Compare the floating of hydrometer in a diet cola with a regular
soft drink
How could the hydrometer be modified to increase
A large tub of ice and water holds cans of both regular and
diet pop. Some cans some don What can you surmise regarding their
content?
POST-LAB Questions 1. Compare the floating of a hydrometer in a diet cola with a regular soft drink. How could the hydrometer be modified to increase accuracy? A large tub of ice...
CHEMISTRY HELP NEEDED!! How do I do this problem? can someone
show me a step-by-step tutorial? I will vote and answer your
response, thanks in advance!
Standard Addition Method Problem Often when doing analytical work, we need to spike our sample because of matrix effects that impact our measurements. This involves making a series of solutions that include increasing amounts of a standard solution of known concentration along with a set amount of the unknown solution, diluting to a mark...
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