Li, „CoO, is an anode for lithium batteries. Cobalt is present as a mixture of Co(III) and Co(II). Most preparations also contain inert lithium salts and moisture. To find the stoichiometry, Co was measured by atomic absorption and its average oxidation state was measured by a potentiometric titration.43 For the titration, 25.00 mg of solid were dissolved under N, in 5.000 mL containing 0.1000 M Fe2+ in 6 M H,SO, plus 6 M H, PO, to give a clear pink solution: Co+ + Fe2+ - Co2+ + Fe3+ Unreacted Fe2+ required 3.457 mL of 0.01487 M K,Cr,0, for complete titration. How many mmol of Co³ + are contained in 25.00 mg of the material? mmol of Co3 + mmol Atomic absorption found 56.4 wt% Co in the solid. What is the average oxidation state of Co? average oxidation state of Co: Find y in the formula Li, 4COO,. y = What is the theoretical quotient wt% Li/wt% Co in the solid? wt% Li wt% Co The observed quotient, after washing away inert lithium salts, was 0.1388 ± 0.0006. Is the observed quotient consistent with the average cobalt oxidation state? O yes no

Li, „CoO, is an anode for lithium batteries. Cobalt is present as a mixture of Co(III) and Co(II). Most preparations also contain inert lithium salts and moisture. To find the stoichiometry, Co was measured by atomic absorption and its average oxidation state was measured by a potentiometric titration.43 For the titration, 25.00 mg of solid were dissolved under N, in 5.000 mL containing 0.1000 M Fe2+ in 6 M H,SO, plus 6 M H, PO, to give a clear pink solution: Co+ + Fe2+ - Co2+ + Fe3+ Unreacted Fe2+ required 3.457 mL of 0.01487 M K,Cr,0, for complete titration. How many mmol of Co³ + are contained in 25.00 mg of the material? mmol of Co3 + mmol Atomic absorption found 56.4 wt% Co in the solid. What is the average oxidation state of Co? average oxidation state of Co: Find y in the formula Li, 4COO,. y = What is the theoretical quotient wt% Li/wt% Co in the solid? wt% Li wt% Co The observed quotient, after washing away inert lithium salts, was 0.1388 ± 0.0006. Is the observed quotient consistent with the average cobalt oxidation state? O yes no

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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SECTION: CEIT-04-101A 2. Balance the following Tedox reactions using the lon- electror Method. a.) cl02+cl' C12+CIO, ( In acidic medium) b.) CN!" + Mn O4 c.) Crq Oq*+ C,04* y CNU! + Mn0,( in basic Hedium + G*+ co,l in acidic medium) d.) Dr, Bro, + Br- (in oaste meclium)
What is the full equation (not the net ionic equation) for the chemical reaction of 0.001 M Fe(NO3)3 plus 0.0002 M NaSCN diluted up to 10 mL with 0.1M HNO3? Please include the acid that is the diluent.
A 1.000-g sample containing bromide was dissolved in sufficient water to give 100.0 mL. A 50.00 mL aliquot was measured and after acidification, silver nitrate was introduced to precipitate AgBr, which was filtered, washed, and then dissolved in an ammoniacal solution of potassium tetracyanonickelate(II): Ni(CN)42- + 2AgBr(s) → 2Ag(CN)2- + Ni2+ + 2Br- The liberated nickel ion required 11.70 mL of 0.002146 M EDTA. Calculate mmol Ni in the 50.00 mL aliquot. Calculate mmol Br- in the 50.00 mL aliquot. Calculate the percentage of NaBr (102.894) in the 1.000 g sample.
A 1.000-g sample containing bromide was dissolved in sufficient water to give 100.0 mL. A 50.00 mL aliquot was measured and after acidification, silver nitrate was introduced to precipitate AgBr, which was filtered, washed, and then dissolved in an ammoniacal solution of potassium tetracyanonickelate(II): Ni(CN)42- + 2AgBr(s) → 2Ag(CN)2- + Ni2+ + 2Br-Nickel ion required 11.70 mL of 0.002146 M EDTAWhat is the percentage of NaBr (102.894) in the 1.000 g sample?
DONT FORGET TO PREDICT THE PRODUCTS
Iron was analyzed by dissolving 1.1324 g sample in concentrated HCL The solution was diluted in H20, Fe(lII) was precipitated as Fe2O3.H20 by adding NH3. After filteration, washing the residue ignited to give 0.2697 g of pure Fe2Os (159.69 g/mol). Calculate %Fe (55.847g/mol) in the sample. O 16.66 % O 69.12 % O 54.21 % 45.21 % 33.32 % hp
An unknown sample weighing 1.5098 g was acidified with 3.0 M H2SO4 to dissolve the copper compounds and diluted with 30 mL distilled water. This was followed by the addition of excess KI producing I2 and CuI precipitate from Cu2+ (Reaction 1). Then, the liberated I2 reacted with the excess KI forming triiodide anion (Reaction 2), which was then titrated with Na2S2O3 titrant (Reaction 3). This entire solution required 17.60 mL of the titrant to reach the starch end point. What are the balanced chemical equations for reactions 1-3? What is the mole ration between Cu2+ and S2O32-?
1. A 0.9882 gram sample of iron ore is dissolved, the iron reduced to Fe2+, and the solution was titrated with 36.40 mL of 0.02065 M KMnO4 in acid solution. (a) Write the titration reaction. (b) Calculate the %FeO (M.M. = 71.85) in the sample. 2. A sample of primary standard grade K2Cr2O7 (MM = 294.20) weighing 0.2153 g is dissolved, the solution acidified and excess KI added. The liberated I2 requires 44.86 mL of the Na2S2O3 for titration. (a) Write the titration reaction. (b) Calculate the molarity of the titrant solution. Box the final answer.
A volume of 2.5 ml was taken from a hypothetical sample containing (3 ) valent antimony and (3 ) valent iron ions and consumption was 16.4 mL when titration was performed with 0.1004 N KMnO4. Another 2.5 mL taken was titrated with the same KMnO4 solution after being reduced with Zn and 26.5 mL was consumed. Calculate the %concentrations of these ions in the solution according to these given ones. (Fe:56; Sb: 121,8; K:39; Mn:55; O:16; Zn: 65,4)
Hh.88.
A mined alloy sample weighing 2.0840 g is dissolved in minimal amounts of concentrated HNO3 before diluted to 50 mL. Ten mL of this diluted sample was titrated using 0.091 M KSCN and required 14.20 mL to reach the endpoint. Calculate the concentration of silver (%w/w) in the mined alloy. (Hint: A dilution factor (DF) is needed in the formula.) Titration reaction: Agt + SCN- → A9SC'N(s) FW: Ag = 107.87 %3D
A solution of I3- was standardized by titrating freshly dissolved arsenious oxide (As4O6, FM 395.683). The titration of 25.00 mL of a solution prepared by dissolving 0.3663 g of As4O6 in a volume of 100.0 mL required 31.77 mL of I3-. Calculate the molarity of the I3- solution.