3. An unknown NiCl2 solution is diluted by mixing 2.00 mL of the original sample with 3.00 mL of distilled water, and the absorbance of the diluted sample is measured at 725 nm. If the dilute solution has an optical density of 0.385, calculate the concentration of NiCl2 in the original (undiluted) sample.

3. An unknown NiCl2 solution is diluted by mixing 2.00 mL of the original sample with 3.00 mL of distilled water, and the absorbance of the diluted sample is measured at 725 nm. If the dilute solution has an optical density of 0.385, calculate the concentration of NiCl2 in the original (undiluted) sample.

Chemistry & Chemical Reactivity

9th Edition

ISBN:9781133949640

Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Publisher:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel

Chapter4: Stoichiometry: Quantitative Information About Chemical Reactions

Section4.8: Stoichiometry Of Reactions In Aqueous Solution-titrations

Problem 2RC

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2. You add 10.00 ml of a 0.630 M methyl red solution to a 100.00 ml volumetric flask. You then add small volumes of sodium acetate and acetic acid solutions to adjust the pH, and then fill the 100 mL volumetric flask to the mark with deionized water. You then make a spectroscopic measurement and obtain absorbance values of 0.253 at 520 nm and 0.079 at 420 nm. What is the concentration of [HIn] in the solution. Remember to use M;V1 = M2V2 as the first step in the calculation process. Hint: see eq. 6 in the lab manual A$20, = 0.367 A520, = 0.010 A420, - 0.012 A420, = 0.275 O 4.30 x 102 O 0.430 O 4.18 x 102 O 0.418
2. Do you observe any change in the form of the absorbance bands while moving from nonpolar to polar solvents?
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.
2. Discuss the different factors that affect the absorbance of a solution.
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?
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What is the molarity of p-nitroaniline in a solution if the absorbance is 0.504 assuming a path length of 1.00 cm?
1) A Chem 102 Student prepared a cobalt coordination compound. Parts "a-c" refer to this problem. a) Next, she analyzed the cobalt content of the compound by preparing a series of known concentration cobalt solutions and prepared a Beer's law graph of absorbance (Y) versus concentration(X). The equation of the line was determined using Excel to be: Y=7.50 X the coordination compound and ultimately diluted it to a total volume of 100.0 mL and measured its absorbance to be 0.310. Calculate the percent cobalt (by mass) in the compound. Where X is concentration in Molarity. She weighed 1.1050 g of
1) Calculate the molar extinction coefficient (molar absorptivity) of tartrazine in units of 1/(M·cm). Assume a cuvette path length of 1.00 cm. 2) If Ana determines the absorbance of an unknown tartrazine sample to be 0.662, what is the concentration of the sample in µM?
Suppose that you follow the procedure and find the absorbance of the final solution to be 0.475. What is the concentration of Fe (mg/L) in the final solution?
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