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 8.57x10-6 M.What was the concentration of the original solution? Express the concentration to three significant figures with the appropriate units. • View Available Hint(s) µA ? original concentration of Fe²+ = Value Units Submit

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 8.57x10-6 M.What was the concentration of the original solution? Express the concentration to three significant figures with the appropriate units. • View Available Hint(s) µA ? original concentration of Fe²+ = Value Units Submit

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

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�L of the sample and injecting it into a cuvette already containing 2.00 mLmL of water (total volume is 2.00 mLmL + 100.0 μL�L). The absorbance value of the diluted solution corresponded to a concentration of 6.22×10−6 M � . What was the concentration of the original solution?
After creating her standard curve for absorption versus the concentration (M) of FD&C Red 40 and processing her data, Sally found that her drinking strength Kool-Aid sample had a concentration of 4.692 x 10–5 M. If 0.132 grams of Kool-Aid powder was used to prepare an 8-fl oz cup of her assigned flavor, what is the percent by mass of FD&C Red 40 in her Kool-aid powder? Report your answer as a percentage with two places after the decimal. Do not include the percentage sign in your answer. Pay attention to units. You are trying to find the mass percentage of red dye, so you need to know each variable in the equation in Appendix B. Note that the percent by mass equation should be multiplied by 100. There may be some useful conversion factors in the experimental procedure.
A chemist needs to create a series of standard Cu2+(aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 25.0025.00 mL of a 2.552.55 M Cu2+(aq) stock solution to a 500.0 volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu2+(aq) solution in the 100.0 mL volumetric flask.
After creating her standard curve for absorption versus the concentration (M) of FD&C Red 40 and processing her data, Sally found that her drinking strength Kool-Aid sample had an FD&C Red 40 concentration of 1.086 x 10–5 M. If 0.133 grams of Kool-Aid powder was used to prepare an 8-fl oz cup of her assigned flavor, what is the percent by mass of FD&C Red 40 in her Kool-aid powder?
What are the differences between systematic and random errors and how do they effect accuracy and precision? In what circumstances would you use standard addition (versus a normal calibration curve) to determine the amount of an analyte in a sample? A urine sample, containing analyte Z is analysed by the standard addition method where 5 mL of the original sample was mixed with increasing amounts of a Z standard and each solution diluted to a volume of 50 mL prior to analysis. A plot of the final concentration of the standard in each of the 50 mL samples (x axis) versus The measured signal from the analysis of each 50 mL sample (on y axis) produced a straight line with the general equation: y = 44.72x + 4.06 what was the final concentration of Z in the 50 mL standard addition sample? what was the initial concentration of Z in the original urine sample?
A stock solution of 0.225 +/- 0.003 M NaNO2 was transferred to a 100 mL volumetric flask (class A) and diluted to the mark. If 7 mL of the stock solution was transferred using one 5-mL and two 1-mL volumetric pipettes, what is the new concentration of the solution and the uncertainty?
Julie has been asked to measure the concentration of a sample solution using a spectrophotometer. After a first attempt, she realizes that, to make the measurement, she must first dilute the sample solution. Julie transfers 2.3 mL2.3 mL of the sample to a 250 mL250 mL volumetric flask and fills the rest of the flask with water to the 250 mL250 mL line. She then uses the spectrophotometer to measure the concentration of the dilute solution as 5.5×10−5 M.5.5×10−5 M. What is the concentration of the starting sample solution? sample solution concentration: M
Julie has been asked to measure the concentration of a sample solution using a spectrophotometer. After a first attempt, she realizes that, to make the measurement, she must first dilute the sample solution. Julie transfers 1.3 mL1.3 mL of the sample to a 250 mL250 mL volumetric flask and fills the rest of the flask with water to the 250 mL250 mL line. She then uses the spectrophotometer to measure the concentration of the dilute solution as 5.5×10−5 M.5.5×10−5 M. What is the concentration of the starting sample solution?
To prepare a standard solution of Mn2+, a 0.250 g sample of Mn is dissolved in 10 mL of concentrated HNO3 (measured with a graduated cylinder). The resulting solution is quantitatively transferred to a 100-mL volumetric flask and diluted to volume with distilled water. A 10-mL aliquot of the solution is pipeted into a 500-mL volumetric flask and diluted to volume.a. Express the concentration of Mn in mg/L, and estimate its uncertainty using a propagation of uncertainty.b. Can you improve the concentration’s uncertainty by using a pipet to measure the HNO3, instead of a graduated cylinder?
The method of standard additions was used to determine nitrite in a soil sample. A 1.00-mL portions of the soil extract sample was transferred to four 25-mL volumetric flasks. To each flask, increment volumes of a 1.00 x10-3M nitrite was added according to the table below. A colorimetric reagent was added to each flask to convert the nitrite into a colored product, and finally diluted to volume. What is the concentration of the nitrite in the soil extract based on the absorbance data below (with blank correction included)? Vol. of standard nitrite added, ml Absorbance 5.00 0.079 10.00 0.161 15.00 0.236 20.00 0.318 25.00 0.403
From the following data, calculate the concentration of the analyte in the sample read at 700 nm: Absorbance of unknown sample = 0.807 Absorbance of a 130 mg/dl standard = 0.234 Do not answer in image format. Maintain accuracy and quality in your answer. Answer completely.
A 0.500g sample is analyzed spectrophotometrically for manganese by dissolving it in acid and transferring to a 250 mL flask and diluting to volume. Three aliquots ae analyzed by transferring 50 mL portions with a pipet to 500 mL Erlenmeyer flask and reacting with an oxidizing agent, potassium peroxydisulfate, to convert the manganese to permanganate. After reaction, these are quantitatively transferred to 250 mL volumetric flasks, diluted to volume and measured spectrophotometrically. By comparison with standards, the average concentration of the final solution is determined to be 1.25 x 10^-5M. What is the percent manganese in the sample?