chemhelp7The researcher determined the Pb content of water sample from a river suspected to be contaminated with Pb from a nearby factory by complexing with cyanidine and the absorbance measured was 0.405. What is the lead content of the water sample?a. 4.23 ppmb. 4.28 ppmc. 207 ppmd. 333 ppm Cyanidin is found in intensely colored flowers. A researcher complexed the flower extract to Lead (Pb)and formed a deep purple color. Cyanidin is an eco-friendly ligand that can be used in UV-Vis analysis.Instead of using toxic and expensive reagents, this was employed by the researcher. PbCl2 (278.1g/mol) of a mass 0.090 g was used in the experiment. It was dissolved in 100.0 mL of distilled, de-ionized water to prepare the stock solution. The X max was determined as follows:X (Wavelength, nm)400420440460480500520540A (Absorbance)0.080.100.200.250.300.400.500.60A (Wavelength, nm)560580600620640660680700A (Absorbance)0.500.400.300.250.200.100.050.03The researcher made a standard calibration curve by diluting the 10.00 mL, 20.00mL, 30.00mL, 40.00mL, and 50.00 mL solutions from the stock. Water was filled up to the 100-mL mark of the volumetricflasks. The absorbance of the solutions were then obtained, and the data are shown below.Concentration (ppm)Absorbance0.0190.00180.00.20270.00.30360.00.43450.00.55

Plot the calibration curve first to get graph equation in excel.

chemhelp7 The researcher determined the Pb content of water sample from a river suspected to be contaminated with Pb from a nearby factory by complexing with cyanidine and the absorbance measured was 0.405. What is the lead content of the water sample? a. 4.23 ppm b. 4.28 ppm c. 207 ppm d. 333 ppm

chemhelp7 The researcher determined the Pb content of water sample from a river suspected to be contaminated with Pb from a nearby factory by complexing with cyanidine and the absorbance measured was 0.405. What is the lead content of the water sample? a. 4.23 ppm b. 4.28 ppm c. 207 ppm d. 333 ppm

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.6QAP

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A method for testing the presence of unreacted salicylic acid in your aspirin synthesis is to add a 1% FeCl3(aq) solution to observe a color change (or not). If a magenta color forms, what has occurred? Select one: The ester group formed a bidentate ligand with the free Fe3+ in solution. The phenol group was deprotonated and reacted with free Fe³+ in solution. O The carboxylic acid group was reduced to a secondary alcohol. O A ketone formed producing a smell similar to nail polish remover
4. Copper (II) sulfate pentahydrate is reacted with potassium oxalate monohydrate to form solid potassium bis(oxalato)cuprate(II) dihydrate. Considering the yield of reaction is 70% and ligand is used 10% excess, how many grams of copper (II) sulfate pentahydrate and potassium oxalate monohydrate should be used to produce 1.54 g of the complex? CUSO4.5H,O (aq) K,SO4(aq) + 2 K,C,04.H,0 (aq) + 3H,O → K,Cu(C,O,)2.2H,O
Consider the following reaction:Al + 3KOH + 3H2C2O4 ∙ 2H2O → K3Al(C2O4)3 ∙ 3H2O + 6HO + (3/2)H21.00 g 20.0 mL 14.0 g6.00 M What is the theoretical yield of the complex formed in the reaction?
2 Ba2+ (aq) + Cr20,2 (aq) + H2O (I) 2 BaCro4 (s) + 2 H* (aq) Dichromate forms orange aqueous solutions and barium chromate is a white solid. Ba(NO3)2 is placed into a test tube of aqueous K2Cr207 forming a colorless solution with a noticeable amount of white solid at the bottom. Use Le Chatelier's Principles to answer the following questions. A. What would you expect to observe if HC was added to the test tube? Explain why the expected observation occurred. B. What could you add to the test tube to increase the amount of solid that would form? Explain why you chose that substance. C. You cool the test tube and notice an increase in the amount of solid formed in the solution. Explain what that suggests about the above reaction?
3) The complex pentamminecarbonatocobalt(III) nitrate was prepared using the starting materials: 5g of cobalt(II) nitrate hexahydrate, excess concentrated ammonia, 12g of ammonium carbonate, and excess hydrogen peroxide. If the reaction gave 3g of actual product, calculate the percentage yield of the complex? Write equation for the reaction. Answer:
The amount of Fe in a 0.4891-g sample of an ore is determined by titrating with K2Cr207. After dissolving the sample in HCI, the iron is brought into a +2 oxidation state using a Jones reductor. Titration to the diphenylamine sulfonic acid end point requires 36.92 mL of 0.02153 M K2Cr207. Report the ore's iron content as %w/w Fe203. In this problem, which is the indicator ? Fe2+ Fe203 HCI K2Cr207 diphenylamine sulfonic acid
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The cation M²+ reacts with NH3 to form a series of complex ions as follows: M²+ + NH3 M(NH3)²+ K₁ = 10² M(NH3)2+ + NH3 M(NH3)2²+ K₂ = 10³ M(NH3)22+ + NH3 = M(NH3)3²+ K3 = 10² A 1.0 × 10-³ mol sample of M(NO3)2 is added to 1.0 L of 15.0 MNH3 (Kb = 1.8 x 10-5). Choose the dominant species in this solution. O M²+ OM(NH3)²+ OM(NH3)22+ O M(NH3)32+ O M(NO3)2
Use the data provided for stock concentration and mass to calculate the concentrations of each solution. Solution A) A stock solution of 0.0100 M solution of K3[Fe(CN)6] is provided. Calculate the volume of the stock solution needed to prepare 100.0 ml of .00200 M K3[Fe(CN)6]. Deionized water should be used to dilute the solution. Solution B) Calculate the volume of solution A needed to prepare 50.0 ml of .0010 M K3[Fe(CN)6]. Deionized water should be used to dilute this solution.
Suggest a precipitation method for separation of K+ from Na+ and Li+. a. Chloroplatinic acid will precipitate a potassium complex, K2PtCl6, but will not form complexes with sodium or lithium ions. b. Carbonic acid will precipitate a potassium complex, K2CO3, but will not form complexes with sodium or lithium ions. c. Hydrogen sulfide gas will precipitate a potassium complex, K2S, but will not form complexes with sodium or lithium ions. d. Sulfurous acid will precipitate a potassium complex, K2SO3, but will not form complexes with sodium or lithium ions.
You want to determine the amount of iron(III) in acomplex salt. You make a 100.0 mL solution of the complex salt by dissolving 0.0670 g of complex salt with water to the mark on a 100.0 mL volumetric flask. You get an absorbance reading for the iron from the spectrometer of 0.334. The molar absorptivity is determined to be 17605 L/mole∙cm and the pathlength is 1.00 cm. Determine the molarity of iron(III) in solution. Determine the mass percentage of iron(III) in the complex salt.
Based on the metal-complex equilibria experiment, which of the following statements is/are CORRECT? I. Ammonia displaces chloride ions as ligand in the formation of Cu (II) complexes resulting in a green colored solution. II. Chloride ion displaces ammonia as ligand in the formation of Cu (1I) complexes resulting in a dark blue-colored solution. III. Copper (II) hydroxide is formed when a low concentration of ammonia is added to an aqueous solution containing Cu2+ ions. Select one: A. III only B. I only C. Il only D. both Il and III F. both Land I| O O O