Outline a method for the determination of K+ based on argentometry. Write balanced equations for the chemical reactions.
> What mass of Cu1IO322 can be formed from 0.475 g of CuSO4 5H2O?
> Define buffer capacity.
> If the following half-cells are the right-hand electrode in a galvanic cell with a standard hydrogen electrode on the left, calculate the cell potential. If the cell were shorted, indicate whether the electrodes shown would act as an anode or a cathode.
> calculate the potential of a platinum electrode immersed in a solution that is a. 0.0513 M in K4Fe1CN26 and 0.00589 M in K3Fe1CN26. b. 0.0300 M in FeSO4 and 0.00825 M in Fe21SO423. c. buffered to a pH of 4.85 and saturated with H2 at 1.00 atm. d. 0
> calculate the potential of a platinum electrode immersed in a solution that is a. 0.0160 M in K2PtCl4 and 0.2450 M in KCl. b. 0.0650 M in Sn1SO422 and 3.5 3 1023 M in SnSO4. c. buffered to a pH of 6.50 and saturated with H21g2 at 1.00 atm. d. 0.0
> Use activities to calculate the electrode potential of a hydrogen electrode in which the electrolyte is 0.0200 M HCl and the activity of H2 is 1.00 atm.
> Calculate the potential of a zinc electrode immersed in
> Calculate the potential of a copper electrode immersed in
> Consider the following oxidation/reduction reactions: a. Write each net process in terms of two balanced half-reactions. b. Express each half-reaction as a reduction. c. Arrange the half-reactions in (b) in order of decreasing effectiveness as electron
> Consider the following oxidation/reduction reactions: a. Write each net process in terms of two balanced half-reactions. b. Express each half-reaction as a reduction. c. Arrange the half-reactions in (b) in order of decreasing effectiveness as electron
> Identify the oxidizing agent and the reducing agent on the left side of each equation in Problem 16-9; write a balanced equation for each half-reaction.
> Calculate the solubility of the solutes in Problem 7-10 for solutions in which the anion concentration is 0.030 M.
> Generate the solubility-product expression for a. CuBr. b. MgCO3. C. PbCl2. d. CaSO4. e. Ag3AsO4.
> Write balanced net ionic equations for the following reactions. Supply H+ and/or H O2 as needed to obtain balance.
> Average human blood contains 300 nmoles of hemoglobin(Hb) per liter of plasma and 2.2 mmol per liter of whole blood. Calculate a. The molar concentration in each of these media. b. pHb in plasma in human serum.
> Identify the oxidizing agent and the reducing agent on the left side of each equation in Problem 16-7; write a balanced equation for each half-reaction.
> Write balanced net ionic equations for the following reactions. Supply H+ and/or H O2 as needed to obtain balance.
> The standard electrode potential for the reduction of Ni2+ to Ni is −. 0 25 V. Would the potential of a nickel electrode immersed in a 1.00 M NaOH solution saturated with Ni(OH 2) be more negative than E 0Ni2+ /Ni or less? Explain.
> In what respect is the Fajans method superior to the Volhard method for the titration of chloride ion?
> Write chemical formulas for the following complex ions:
> Explain how stepwise and overall formation constants are related.
> Write chemical equations and equilibrium-constant expressions for the stepwise formation of
> When a 100.0-mL portion of a solution containing 0.500 g of AgNO3 is mixed with 100.0 mL of a solution containing 0.300 g of K2CrO4, a bright red precipitate of Ag2CrO4 forms. a. Assuming that the solubility of Ag2CrO4 is negligible, calculate the mass
> Describe three general methods for performing EDTA titrations. What are the advantages of each?
> The data in the following table were obtained during a colorimetric determination of glucose in blood serum. a. Assuming a linear relationship between the variables, find the least-squares estimates of the slope and intercept. b. What are the standard de
> Why are multidentate ligands preferable to unidentate ligands for complexometric titrations?
> Define a. ligand. b. chelate. c. tetradentate chelating agent. d. adsorption indicator. e. argentometric titration. f. conditional formation constant. g. EDTA displacement titration. h. water hardness.
> What is a buffer solution, and what are its properties?
> A 50.0-mL portion of a solution containing 0.200 g of BaCl2 . 2H2O is mixed with 50.0 mL of a solution containing 0.300 g of NaIO3. Assume that the solubility of Ba1IO322 in water is negligibly small and calculate a. The mass of the precipitated Ba1IO32
> The following are relative peak areas for chromatograms of standard solutions of methyl vinyl ketone (MVK). a. Determine the coefficients of the best fit line using the least-squares method. b. Construct an ANOVA table. c. Plot the least-squares line as
> Seawater contains an average of 1.08 × 103 ppm of Na+ and 270 ppm of SO42-. Calculate a. The molar concentrations of Na+ and SO2- given that the average density of seawater is 1.02 g/mL. b. The pNa and pSO4 for seawater.
> A 6.881-g sample containing magnesium chloride and sodium chloride was dissolved in sufficient water to give 500 mL of solution. Determination of the chloride content of a 50.0-mL aliquot resulted in the formation of 0.5923 g of AgCl. The magnesium in a
> The following data were obtained in calibrating a calcium ion electrode for the determination of pCa. A linear relationship between the potential and pCa is known to exist. a. Plot the data, and draw a line through the points by eye. b. Find the least-s
> At 25°C, what is the hydronium ion concentration in a. 0.100 M chloroacetic acid? b. 0.100 M sodium chloroacetate? c. 0.0300 M methylamine? d. 0.0300 M methylamine hydrochloride? e. 1.50 3 1023 M aniline hydrochloride? f. 0.200 M HIO3?
> What mass in grams of CO2 is evolved in the complete decomposition of a 2.300-g sample that is 38.0% MgCO3 and 42.0% K2CO3 by mass?
> A solution contains 1.569 mg of CoSO4 (155.0 g/mol) per milliliter. Calculate
> A solution was prepared by dissolving about 3.0 g of Na2H2Y⋅2H2O in approximately 1 L of water and standardizing against 50.00-mL aliquots of 0. 00397MMg2+ An average titration of 30.27 mL was required. Calculate the molar concentration of the EDTA.
> An EDTA solution was prepared by dissolving 3.426 g of purified and dried Na2H2Y · 2H2O in sufficient water to give 1.000 L. Calculate the molar concentration, given that the solute contained 0.3% excess moisture (see Section 15D-1).
> Why is a small amount of MgY2− often added to a water specimen that is to be titrated for hardness?
> The sulfate ion concentration in natural water can be determined by measuring the turbidity that results when an excess of BaCl2 is added to a measured quantity of the sample. A turbidimeter, the instrument used for this analysis, was calibrated with a s
> Given an overall complex formation reaction of with an overall formation constant of βn, show that the following relationship holds:
> Propose a complexometric method for the determination of the individual components in a solution containing
> Write a conditional overall formation constant for [Fe(Ox)3] 3− in terms of α2 for oxalic acid and the β value for the complex. Also express the conditional constant in terms of concentrations as in Equation 15-20.
> Write conditional formation constants for 1:1 complexes of Al(III) with each of the ligands in Problem 15-11. Express these constants in terms of the α value and the formation constant and in terms of concentrations as in Equation 15-20.
> Write equations in terms of the acid dissociation constants and [H+] for the highest alpha value for each of the following weak acid ligands:
> The phosphorus in a 0.3019-g sample was precipitated as the slightly soluble 1NH423PO4 . 12MoO3. This precipitate was filtered, washed, and then redissolved in acid. Treatment of the resulting solution with an excess of Pb21 resulted in the formation of
> Convert the following p-functions to molar concentrations: a. pH = 1.102. b. pOH = 0.0057. c. pBr = 7.77. d. pCa = -0.221. e. pLi = 12.35. f. pNO3 = 0.054. g. pMn = 0.135. h. pCl = 8.92.
> What is the difference between molar species concentration and molar analytical concentration?
> Outline a method for the determination of K+ based on argentometry. Write balanced equations for the chemical reactions.
> Why does the charge on the surface of precipitate particles change sign at the equivalence point of a titration?
> A method for the determination of the corticosteroid methylprednisolone acetate in solutions obtained from pharmaceutical preparations yielded a mean value of 3.7 mg mL-1with a standard deviation of 0.3 mg mL-1. For quality control purposes, the relative
> Briefly explain why the sparingly soluble product must be removed by filtration before you back-titrate the excess silver ion in the Volhard determination of
> Give two reasons why ( ( 3 2 KH IO is preferred over benzoic acid as a primary standard for a 0.010 M NaOH solution.
> Why is it common practice to boil the solution near the equivalence point in the standardization of Na2CO3 with acid?
> The boiling points of HCl and CO2 are nearly the same (285°C and 278°C). Explain why CO2 can be removed from an aqueous solution by boiling briefly while essentially no HCl is lost even after boiling for 1 hour or more.
> Four analysts perform replicate sets of Hg determinations on the same analytical sample. The results in ppb Hg are shown in the following table: a. State the appropriate hypotheses. b. Do the analysts differ at the 95% confidence level? At the 99% confi
> Describe how Na2CO3 of primary-standard grade can be prepared from primary-standard NaHCO3.
> Why is nitric acid seldom used to prepare standard acid solutions?
> A 10.00-mL sample of vinegar (acetic acid, CH3COOH) was pipetted into a flask, two drops of phenolphthalein indicator were added, and the acid was titrated with 0.1008 M NaOH a. If 45.62 mL of the base was required for the titration, what was the molar c
> At 25°C, what are the molar H3O1 and OH2 concentrations in a. 0.0300 M HCOOH? b. 0.0600 M HN3? c. 0.200 M ethylamine? d. 0.100 M trimethylamine? e. 0.250 M C6H5COONa (sodium benzoate)? f. 0.0750 M CH3CH2COONa? g. 0.250 M hydroxylamine hydrochloride? h. 0
> Calculate the equivalent mass of oxalic acid dehydrateH2C2O4 2H2O,12066g/mol when it is titrated to (a) a bromocresol green end point and (b) a phenolphthalein end point.
> Define the equivalent mass of (a) an acid and (b) a base
> The seller of a mining claim took a random ore sample that weighed approximately 5 lb and had an average particle diameter of 5.0 mm. Inspection revealed that about 1% of the sample was argentite (see Problem 6-9), and the remainder had a density of abou
> How did the definition of the mole change with the 2019 redefinition of SI base units?
> A series of solutions containing NaOH,Na2CO3 , and NaHCO3 , alone or in compatible combination, was titrated with 0.1202 M HCl. In the following table are the volumes of acid needed to titrate 25.00-mL portions of each solution to (1) a phenolphthalein a
> A series of solutions containing NaOH,Na3AsO4 , and Na2HAsO4 , alone or in compatible combination, was titrated with 0.08601 M HCl. In the following table are the volumes of acid needed to titrate 25.00-mL portions of each solution to (1) a phenolphthale
> A 0.6407-g sample containing chloride and iodide ions gave a silver halide precipitate weighing 0.4430 g. This precipitate was then strongly heated in a stream of Cl2 gas to convert the AgI to AgCl; on completion of this treatment, the precipitate weighe
> Calculate the volume of 0.07731 M NaOH needed to titrate a. 25.00 mL of a solution that is 0.03000 M in HCl and 0.01000 M in H3PO4 to a bromocresol green end point. b. the solution in (a) to a thymolphthalein end point. c. 30.00 mL of 006407MNaH 2PO
> Calculate the volume of 0.06452 M HCl needed to titrate a. 20.00 mL of 005522MNa3PO4 to a thymolphthalein end point. b. 25.00 mL of 005522MNa3PO4 to a bromocresol green end point. c. 40.00 mL of a solution that is 0.02199 M in Na3PO4 and 0.01714
> A 0.5000-g sample containing NaHCO3 , Na2CO3 , and H2O was dissolved and diluted to 250.0 mL. A 25.00-mL aliquot was then boiled with 50.00 mL of 0.01255 M HCl. After cooling, the excess acid in the solution required 2.34 mL of 0.01063 M NaOH when titra
> A 1.421-g sample of commercial KOH contaminated by K2CO3 was dissolved in water, and the resulting solution was diluted to 500.0 mL. A 50.00-mL aliquot of this solution was treated with 40.00 mL of 0.05567 M HCl and boiled to remove CO2 The excess acid
> A 1.219-g sample containing (NH4)2SO4, NH4NO3, and nonreactive substances was diluted to 200 mL in a volumetric flask. A 50.00-mL aliquot was made basic with strong alkali, and the liberated NH3 was distilled into 30.00 mL of 0.08421 M HCl. The excess HC
> A 0.8835-g sample of a wheat flour was analyzed by the Kjeldahl procedure. The ammonia formed was distilled into 50.00 mL of 0.05078 M HCl; a 8.04-mL back-titration with 0.04829 M NaOH was required. Calculate the percentage of protein in the flour.
> Calculate the p-functions for each ion in a solution that is A. 0.0200 M in NaBr. b. 0.0300 M in BaBr2. c. 4.5 × 10-3 M in Ba(OH)2. d. 0.020 M in HCl and 0.010 M in NaCl. e. 7.2 × 10-3 M in CaCl2 and 8.2 × 10-3 M in BaCl2. f. 2.8 × 10-8 M in Zn(NO3)2
> A 0.5843-g sample of a plant food preparation was analyzed for its N content by the Kjeldahl method, the liberated NH3 being collected in 50.00 mL of 0.1062 M HCl. The excess acid required an 11.89 mL back-titration with 0.0925 M NaOH. Express the result
> The data in the accompanying table represent the concentration of glucose in the blood serum of an adult patient. On four consecutive days, a blood sample was drawn from the patient and analyzed in triplicate. The variance for a given sample is an estima
> Calculate the mass in grams of protein in a 5.00-oz can of tuna in Problem 14-35.
> A 0.7891-g sample of a mixture consisting solely of sodium bromide and potassium bromide yields 1.2895 g of silver bromide. What are the percentages of the two salts in the sample?
> A 0.917-g sample of canned tuna was analyzed by the Kjeldahl method. A volume of 20.59 mL of 0.1249 M HCl was required to titrate the liberated ammonia. Calculate the percentage of nitrogen in the sample.
> The Merck Index indicates that 10 mg of guanidine, CHN53 , may be administered for each kilogram of body mass in the treatment of myasthenia gravis. The nitrogen in a 4-tablet sample that had a total mass of 7.66 g was converted to ammonia by a Kjeldahl
> Neohetramine, C16H22ON428637g/mol, is a common antihistamine. A 0.1247-g sample containing this compound was analyzed by the Kjeldahl method. The ammonia produced was collected in H3BO3 ; the resulting HBO2 3 was titrated with 26.13 mL of 0.01477 M
> A 0.9826-g sample containing dimethyl phthalate, C6H4COOCH3 219419g/mol, and unreactive species was refluxed with 50.00 mL of 0.1104 M NaOH to hydrolyze the ester groups (this process is called saponification). C6H4 COOCH3 2 2OHC6H4 COO2
> The digestion of a 0.1417-g sample of a phosphorus-containing compound in a mixture of HNO3 and H2SO4 resulted in the formation of CO2 ,H2O, and HPO34 Addition of ammonium molybdate yielded a solid having the composition NH43 PO4 12MoO318763g/
> Air was bubbled at a rate of 30.0 L/min through a trap containing 75 mL of 1% H2O2 H2O2 SO2 H2SO4 After 10.0 minutes, the H2SO4 was titrated with 10.95 mL of 0.00242 M NaOH. Calculate concentration of SO2 in parts per million (that is, mLSO2 106m
> A 3.00-L sample of urban air was bubbled through a solution containing 50.0 mL of 00116MBaOH2 , which caused the CO2 in the sample to precipitate as BaCO3 The excess base was back-titrated to a phenolphthalein end point with 23.6 mL of 0.0108 M HC
> A dilute solution of an unknown weak acid required a 28.94-mL titration with 0.1062 M NaOH to reach a phenolphthalein end point. The titrated solution was evaporated to dryness. Calculate the equivalent mass of the acid if the sodium salt was found to we
> Calculate the pH of water at 25°C and 50°C. The values for pKw at these temperatures are 13.99 and 13.26, respectively.
> In the determination of lead in a paint sample, it is known that the sampling variance is 10 ppm while the measurement variance is 4 ppm. Two different sampling schemes are under consideration: Scheme a: Take five sample increments and blend them. Perfor
> The efficiency of a particular catalyst is highly dependent on its zirconium content. The starting material for this preparation is received in batches that assay between 68% and 84% ZrCl4. Routine analysis based on precipitation of AgCl is feasible, it
> The aluminum in a 2.200-g sample of impure ammonium aluminumsulfate was precipitated with aqueous ammonia as the hydrous Al2O3 xH2O. The precipitate was filtered and ignited at 1000°C to give anhydrous Al2O3, which weighed 0.3006 g. Express the result o
> A 0.1401-g sample of a purified carbonate was dissolved in 50.00 mL of 0.1140 M HCl and boiled to eliminate CO2 Back-titration of the excess HCl required 24.21 mL of
> A 25.00-mL sample of a household cleaning solution was diluted to 250.0 mL in a volumetric flask. A 50.00-mL aliquot of this solution required 43.04 mL of 0.1776 M HCl to reach a bromocresol green end point. Calculate the mass/volume percentage of NH3 in
> The active ingredient in Antabuse, a drug used for the treatment of chronic alcoholism, is tetraethylthiuram disulfide, (296.54 g/mol). The sulfur in a 0.4169-g sample of an Antabuse preparation was oxidized to SO2 , which was absorbed in H2O2 to give H2
> The benzoic acid extracted from 86.7 g of catsup required a 15.61-mL titration with 0.0654 M NaOH. Express the results of this analysis in terms of percent sodium benzoate (144.10 g/mol).
> The formaldehyde (HCHO) content of a pesticide preparation was determined by weighing 0.2985 g of the liquid sample into a flask containing 50.0 mL of 0.0959 M NaOH and 50 mL of 3% H2O2Upon heating, the following reaction took place: OHHCHOH2O2 H
> A 0.7041-g sample of impure mercury(II) oxide was dissolved in an unmeasured excess of potassium iodide. Reaction: HgOs4IH2OHgI242OH Calculate the percentage of HgO in the sample if titration of the liberated hydroxide required 40.67 mL of
> Titration of a 0.7513-g sample of impure Na2B4O7 required 30.79 mL of 0.1129 M HCl (see Problem 14-16f for reaction). Express the results of this analysis in terms of percent a. Na2B4O7 b. Na2B4O7 10H2O c. B2O3 d. B.
> A 25.0-mL aliquot of vinegar was diluted to 250 mL in a volumetric flask. Titration of 50.0mL aliquots of the diluted solution required an average of 25.23 mL of 0.09041 M NaOH. Express the acidity of the vinegar in terms of the percentage (w/v) of aceti
> A 50.00-mL sample of a white dinner wine required 24.57 mL of 0.03291 M NaOH to achieve a phenolphthalein end point. Express the acidity of the wine in grams of tartaric acid H2C4H4O6 ;15009g/mol per 100 mL. (Assume that two hydrogens of the acid ar
> a. Compare the masses of potassium hydrogen phthalate (204.22 g/mol), potassium hydrogen iodate (389.91 g/mol), and benzoic acid (122.12 g/mol) needed for a 50.00-mL standardization of 0.0600 M NaOH. b. What would be the relative standard deviation in t
