A student prepared this calibration curve: Absorbance 0.6 0.5 0.4 0.3 0.2 0.1 0 Beer's Law Plot: Cobalt (II) Nitrate Standards 0.0000 0.0200 y = 5.5185x -0.0114 R² = 0.9995 0.789 M 0.0283 M 0.9997 M 0.0242 M 0.0400 0.0600 Concentration (M) 0.0800 0.1000 0.1200 Linear regression of the data yields an equation of y = 5.5185x-0.0114 with R² = 0.9995 What is the Molarity of an Unknown Solution that has Absorbance = 0.145

A student prepared this calibration curve: Absorbance 0.6 0.5 0.4 0.3 0.2 0.1 0 Beer's Law Plot: Cobalt (II) Nitrate Standards 0.0000 0.0200 y = 5.5185x -0.0114 R² = 0.9995 0.789 M 0.0283 M 0.9997 M 0.0242 M 0.0400 0.0600 Concentration (M) 0.0800 0.1000 0.1200 Linear regression of the data yields an equation of y = 5.5185x-0.0114 with R² = 0.9995 What is the Molarity of an Unknown Solution that has Absorbance = 0.145

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...

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em1.png chem3.png Part 3: Q9 Average absorbance Flask 8 Flask 9 Flask 10 Flask 11 Part 3: Q9 Flask 8 Flask 9 Flask 10 Flask 11 Part 3: Q10 Flask 8 Flask 9 Flask 10 Flask 11 Q Part 3 0.146 [Fe] -0.002mol/L 0.166 volume 5.00mL 0.215 0.294 [FESCN mol/L) ✪ 4.59* 10 5.18*10* 6.64 x 10 9.08*10* [Fe(mol/L) 5.00 x 10 5.00*10* Y=3362x -0.0083 R¹ 0.9993 5.00 x 10 5.00*10* (Amounts of flask 8 (9 - 11's values are in the spreadsheet) 1:1 Ratio so, Molarity of Fe(NO3))3 = 0.2M Volume of Fe(NO3))3 = 5.00mL 71% Moles of Fe³= Molarity x volume(L) Moles of Fe = 0.2M × 0.005L = 1× 10-³mole 68% [SCN ](mol/ 4 x 10-4 5 x 10-4 7*10* 1*10* الخا chem2.png Concentration of Fe³ 9, X = mole of Fe³1x10³ mole Volume 0.0054 Ⓒ 8, Average absorbance for solution 8 (same for 9 - 11) Average absorbance for flask 8 = sum of all absorbances / number of readings (0.145 +0.147 +0.148) 3 Using equation of calibration curve's line(slope) of best fit, the average absorbances of the unknown concentrations to determine…
You have prepared several dilutions of a standard compound. You measure the absorbance of each solution at 340 nm using a 1 cm cuvette and your results are listed in the table below. Determine the concentration of an unknown sample with an absorbance of 0.085 at 340 nm. Concentration (uM) Absorbance at 340 nm 2. 0.009 4. 0.020 0.061 16 0.111 32 0.189
Calculate the molar concentration of Fe3+ and SCN- in each of the three unknown samples (sample 4,7,and 10) made from Table 2 immediately after each sample was prepared, before the reaction occurs at all.
25.0 g of an impure sample containing cobalt was dissolved in acid and diluted to1000.00 mL. 6.00 mL of this sample was removed, treated appropriately to give a coloredsolution, and then diluted to 250.00 mL. This final solution had an absorbance of 0.410.Calculate the percentage of cobalt (MW = 58.93 g/mol) in the original sample.
After determining the absorbance of several standards of known concentration, the trend line for a calibration curve plotting absorbance (y-axis) against concentration (uM, x-axis) is determined to be y=4.244x+0.0000. The absorbance of a solution of unknown concentration is determined to be 0.604. Calculate the concentration of the unknown solution in microM. Give answer to 3 decimal places
The molar absorptivity constant of a particular chemical is 2.31 M/cm. Determine the concentration of a solution made from this chemical that has an absorbance of 0.521 with a cell path length of 1.04 cm.
6. Blue Blue dye stock solution 0.293 M Absorbance at 630 nm 0.00265 Calibration curve y = 0.0833x A solution is prepared by diluting 2.79 mL of the blue dye stock solution to 25.00 mL. The measured absorbance for the prepared solution is listed in the data table. (a) What is the theoretical molar concentration? [Blue]theoretical x 10 |M (b) What is the experimental molar concentration? [Blue]experimental x 10 M (c) What is the percent error? Percent error (blue) = %
Absorbance Beer-Lambert's Law (Spectrophotometry) #2 To spectrophotometrically determine the mass percent of cobalt in an ore containing cobalt and some inert materials, solutions with known [Co"] are prepared and the absorbance of each of the solutions is measured at the wavelength of optimum absorbance. The data are used to create a calibration plot, shown below. 0.80 0.70- 8 0.60- 0.50- 0.40- 0.30 0.20- 0.10- ++- 0.015 Concentration (M) A 0.6 g sample of the ore is completely dissolved in concentrated HNO3(aq). The mixture is diluted with 2+ water to a final volume of 50.00 mL. Assume that all the cobalt in the ore sample is converted to Co'(aq). a. What is the (Co] in the solution if the absorbance of a sample of the solution is 0.74? b. Calculate the number of moles of CoT(ag) in the 50.00 mL solution. 2+ C. Calculate the mass percent of Co in the 0.630 g sample of the ore.
1.) Beer's Law can be used to find the concentration of a solution by measuring its absorbance. The law is given by ?=???A=ϵbC Where A is the absorbance, ?ϵ is the molar absorptivity, b is the pathlength of the light (the width of the sample cell), and C is the concentration of the solution. A student is analyzing a solution of a metal, and finds that the absorbance of the solution is 0.532. If ?=187 L⋅g−1⋅cm−1ϵ=187 L⋅g−1⋅cm−1 and ?=1 cmb=1 cm , what is the concentration of the metal in solution (in g/L)? * 352 * 2.84×10−32.84×10−3 * 2.84×10−22.84×10−2 * 96.8 2.) How many significant figures does the number 0.00358 have? Group of answer choices a.1 b.2 c.3 d.5 3.) A 10.00 mL solution of a certain food dye has a concentration of 1.47 g /L. What is the total mass of food dye in the solution? Report your answer with the correct number of significant figures.
The molar absorptivity constant of a particular chemical is 2.31 M/cm. Determine the concentration of a solution made from this chemical that has an absorbance of 0.408 with a cell path length of 1.12 cm.
The concentration of a dilute aspirin solution is 0.000530 M 0.000530 M . Standard solutions of this compound were used to prepare a Beer's law plot which gives a slope of 1550.1 M −1 1550.1 M − 1 . What is the expected absorbance value for the aspirin solution?
A medical lab technician creates a standard solutions of percent hemoglobin in whole blood. The technician measures the absorbance of each solution at 520 nm and creates a standard curve of the absorbance versus percent hemoglobin in whole blood and finds the linear equation below, with an R2 of 0.9985. y = 0.0523 x + 0.072 A patient sample has an absorbance of 0.162. Using the standard curve data, calculate the percent hemoglobin in the patient sample