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20.00 mL unknown sample is diluted to 250.0 mL. Absorbance is 0.2430 Absorbance for 70.00 ppm...
Calculate the concentration of the unknown MnO4- sample, given the following standard addition ex...
Calculate the concentration of the unknown MnO4- sample, given the following standard addition experiment. Step 1: A 2.00 mL aliquot of an unknown MnO4- sample was diluted to 250.0 mL and the absorbance measured to be 0.360. Step 2: A 2.00 mL aliquot of an unknown MnO4- sample was placed in a 250.0 mL flask. A 2.00 mL aliquot of a 100.00 ppm MnO4- standard was added to the flask and the absorbance measured to be 0.770.
A 13.0 mL aliquot of a flouride sample solution was diluted to 250 mL in a...
A 13.0 mL aliquot of a flouride sample solution was diluted to 250 mL in a volumetric flask. The F- concentration of this DILUTED sample was determined with a F- ion selective electrode and found to be 3.1 mg/L. What is the concentration of F- in the original, undiluted sample?
A 5.0067 g sample of Na2CrO4 (MW = 161.97 g/mol) is dissolved in 250.0 mL of...
A 5.0067 g sample of Na2CrO4 (MW = 161.97 g/mol) is dissolved in 250.0 mL of water. Assume the solution has a density of 1.00 g/mL. A 50.0 mL aliquot of the solution is then diluted to a final volume of 250.0 mL. What is the concentration of Na+ in the diluted solution in units of parts per million (ppm)?
Part C The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted...
Part C The absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 μL of the sample and injecting it into a cuvette already containing 2.00 mL of water (total volume is 2.00 mL + 100.0 μL). The absorbance value of the diluted solution corresponded to a concentration of 6.70×10−6 M . What was...
Sample (gamma globulin) volume (microliter) water (microliter) dye (microliter) absorbance (A595) 100(microgram/ml) 50 550 400 .037...
Sample (gamma globulin) volume (microliter) water (microliter) dye (microliter) absorbance (A595) 100(microgram/ml) 50 550 400 .037 100(microgram/ml) 100 500 400 .076 100(microgram/ml) 150 450 400 .103 100(microgram/ml) 200 400 400 .133 100(microgram/ml) 250 350 400 .156 100(microgram/ml) 300 300 400 .185 100(microgram/ml) 400 200 400 .219 Unknown 25 (microgram/ml) 575 400 .075 Unknown 50 (microgram/ml) 550 400 .12 Unknown 100 (microgram/ml 500 400 .185 1) what is the amount of (in micrograms) of gamma globulin in the diluted unknown samples?...
The last digit in the answer is four X.X4 A 3.75 mL unknown sample containing red...
The last digit in the answer is four X.X4
A 3.75 mL unknown sample containing red and blue dyes was separated on a solid phase extraction column. As it was eluted from the column, each sample was diluted to a total volume of 50.00 mL in a volumetric flask with the appropriate solvent. UV spectrophotometry was used to determine the amount of dye in the diluted sample. The data collected by the students in the lab are provided below. Sample...
A Bradford assay was carried out to measure protein concentration. The absorbance of five standard samples...
A Bradford assay was carried out to measure protein concentration. The absorbance of five standard samples and two unknown samples are listed in the table below. The Bradford reaction mixture (1 ml) was prepared as follows: 100 μl sample A or sample B + 200 μl Bradford reagent + 700μl 0.9% NaCl solution sample ID concentration (mM) absorbance (O.D.) std 1 100 0.78 std 2 50 0.4 std 3 25 0.18 std 4 12.5 0.08 std 5 0 0 ...
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The dat...
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The data is as following: Concentration (ppm) 10.0 20.0 30.0 40.0 50.0 Absorbance 0.105 0.198 0.330 0.402 0.533 An unknown solid sample (0.1050 g) containing substance X was dissolved in 5.0 mL acidic solution and then transferred to a 100.0 mL volumetric flask and filled with deionized water to the mark. The absorbance of this solution is 0.378. What is...
Question 6 A student prepared an unknown sample by making a dilute solution of the unknown...
Question 6 A student prepared an unknown sample by making a dilute solution of the unknown sample. The dilute sample was prepared by adding 5.0 mL of the unknown sample to a 25.0 mL flask. What is the concentration(mM) of the diluted unknown sample that has an absorbance of 0.270? Write answer to three significant figures. Using the information and answer in question 6, what is the concentration(mM) of the original unknown sample? Write answer to three significant figures. There...
A standard sample was prepared containing 20.00 ppm of an analyte and 10.00 ppm internal standard....
A standard sample was prepared containing 20.00 ppm of an analyte and 10.00 ppm internal standard. The signal readings for these were 0.115 units and 0.321 units respectively. Sufficient internal standard was added to an unknown sample solution to make it contain 15.00 ppm internal standard. This solution gave readings for the analyte and internal standard of 0.266 and 0.275 units respectively. Determine the concentration of the analyte in the unknown sample.
The last digit in the answer is four X.X4
A 3.75 mL unknown sample containing red and blue dyes was separated on a solid phase extraction column. As it was eluted from the column, each sample was diluted to a total volume of 50.00 mL in a volumetric flask with the appropriate solvent. UV spectrophotometry was used to determine the amount of dye in the diluted sample. The data collected by the students in the lab are provided below. Sample...
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The data is as following: Concentration (ppm) 10.0 20.0 30.0 40.0 50.0 Absorbance 0.105 0.198 0.330 0.402 0.533 An unknown solid sample (0.1050 g) containing substance X was dissolved in 5.0 mL acidic solution and then transferred to a 100.0 mL volumetric flask and filled with deionized water to the mark. The absorbance of this solution is 0.378. What is...
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