Questions and Answers of Fundamentals Of Analytical Chemistry

Calculate α0 and α1 for(a) Acetic acid in a solution with a pH of 5.320.(b) Picric acid in a solution with a pH of 1.750.(c) Hypochlorous acid in a solution with a pH of 7.00.(d) Hydroxylamine acid
Calculate the pH after addition of 0.00, 5.00, 15.00, 25.00, 40.00, 49.00, 50.00, 51.00, 55.00, and 60.00 mL of reagent in the titration of 50.0 mL of(a) 0.01000 M chloroacetic acid with 0.01000 M
Calculate the pH after addition of 0.00, 5.00, 15.00, 25.00, 40.00, 45.00, 49.00, 50.00, 51.00, 55.00, and 60.00 mL of 0.1000 M HCl in the titration of 50.00 mL of(a) 0.1500 M ammonia.(b) 0.1500 M
Calculate the pH after addition of 0.00, 5.00, 15.00, 25.00, 40.00, 45.00, 49.00, 50.00, 51.00, 55.00, and 60.00 mL of 0.1000 M NaOH in the titration of 50.00 mL of(a) 0.1000 M HNO2.(b) 0.1000 M
In a titration of 50.00 mL of 0.1000 M ethylamine with 0.1000 M HClO4, the titration error must be no more than 0.05 mL. What indicator can be chosen to realize this goal?
In a titration of 50.00 mL of 0.05000 M formic acid with 0.1000 M KOH, the titration error must be smaller than 0.05 mL. What indicator can be chosen to realize this goal?
A 50.00-mL aliquot of 0.1000 M NaOH is titrated with 0.1000 M HCl. Calculate the pH of the solution after the addition of 0.00, 10.00, 25.00, 40.00, 45.00, 49.00, 50.00, 51.00, 55.00, and 60.00 mL of
What is the pH of a solution that is(a) Prepared by dissolving 3.30 g of (NH4)2SO4 in water, adding 125.0 mL of 0.1011 M NaOH, and diluting to 500.0 mL?(b) 0.120 M in piperidine and 0.010 M in its
What is the pH of a solution that is(a) Prepared by dissolving 6.75 g of lactic acid (90.08 g/mol) and 5.19 g of sodium lactate (112.06 g/mol) in water and diluting to 1.00 L?(b) 0.0430 M in acetic
Calculate the pH of the solution that results when 20.0 mL of 0.2500 M NH3 is(a) Mixed with 20.0 mL of distilled water.(b) Mixed with 20.0 mL of 0.250 M HCl solution.(c) Mixed with 20.0 mL of 0.300 M
Calculate the pH of a solution prepared by(a) Dissolving 1.87 g of picric acid, (NO2)3C6H2OH (229.11 g/mol), in 100 mL of water.(b) Diluting 10.0 mL of the solution in (a) to 100 mL.(c) Diluting 10.0
Calculate the pH of a solution prepared by(a) Dissolving 36.5 g of lactic acid in water and diluting to 500 mL.(b) Diluting 25.0 mL of the solution in (a) to 250 mL.(c) Diluting 10.0 mL of the
Calculate the pH of a solution that is(a) 1.50 x 10-1 M sulfamic acid.(b) 1.50 x 10-2 M sulfamic acid.(c) 1.50 x 10-4 M sulfamic acid.
Calculate the pH of a solution in which the concentration of piperidine is(a) 1.00 x 10-1 M.(b) 1.00 x 10-2 M.(c) 1.00 x 10-4 M.
Calculate the pH of a solution that is(a) 1.50 x 10-1 M NH4Cl.(b) 1.50 x 10-2 M NH4Cl.(c) 1.50 x 10-4 M NH4Cl.
Calculate the pH of a solution that is(a) 1.50 x 10-1 M NaOCl.(b) 1.50 x 10-2 M NaOCl.(c) 1.50 x 10-4 M NaOCl.
Calculate the pH of the solution that results when mixing 15.0 mL of 0.2500 M HCl with 25.0 mL of(a) Distilled water.(b) 0.132 M AgNO3.(c) 0.132 M NaOH.(d) 0.132 M NH3.(e) 0.232 M NaOH.
Calculate the pH of a solution that contains 2.50% (w/w) NaOH and has a density of 1.015 g/mL.
The phosphorous content in ppm was measured for three different soil locations. Five replicate determinations were made on each soil sample. A partial ANOVA table follows:(a) Fill in the missing
Values for Kw at 0, 50, and 100ºC are 1.14 x 10-15, 5.47 x 10-14, and 4.9 x 10-13, respectively. Calculate the pH for a neutral solution at each of these temperatures.
What variables can cause the pH range of an indicator to shift?
Why are the standard reagents used in neutralization titrations generally strong acids and bases rather than weak acids and bases?
What factors affect end-point sharpness in an acid-base titration?
What mass of KIO3 is needed to convert the copper in 0.1570 g of CuSO4 . 5H2O to Cu(IO3)2?
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
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)
Water can be determined in solid samples by infrared spectroscopy. The water content of calcium sulfate hydrates is to be measured using calcium carbonate as an internal standard to compensate for
The data in the following table represent electrode potential E versus concentration c.(a) Transform the data to E versus -log c values.(b) Plot E versus -log c, and find the least-squares estimate
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
Potassium can be determined by flame emission spectrometry (flame photometry) using a lithium internal standard. The following data were obtained for standard solutions of KCl and an unknown
The following atomic absorption results were obtained for determinations of Zn in multivitamin tablets. All absorbance values are corrected for the appropriate reagent blank (cZn = 0.0 ng/mL). The
Atomic emission measurements were made to determine sodium in a blood serum sample. The following emission intensities were obtained for standards of 5.0 and 10.0 ng/mL and for the serum sample. All
The following data represent measurements made on a process for 30 days. One measurement was made each day. Assuming that 30 measurements are enough that X ̅ → μ and s → σ, find the mean of
Copper was determined in a river water sample by atomic absorption spectrometry and the method of standard additions. For the addition, 100.0 μL of a 1000.0-μg/mL Cu standard was added to 100.0 mL
The solubility products for a series of hydroxides areWhich hydroxide has(a) The lowest molar solubility in H2O?(b) The lowest molar solubility in a solution that is 0.35 M in NaOH? BIOOH Kp 4.0 10-
Calculate the solubility-product constant for each of the following substances, given that the molar concentrations of their saturated solutions are as indicated:(a) AgSeCN (2.0 x 10-8 M; products
What CrO4 2- concentration is required to(a) Initiate precipitation of Ag2CrO4 from a solution that is 5.24 x 10-3 M in Ag+?(b) Lower the concentration of Ag+ in a solution to 7.82 x 10-7 M?
What is a buffer solution, and what are its properties?
It can be shown that the buffer capacity iswhere cT is the molar analytical concentration of the buffer.(a) Show that(b) Use the equation in (a) to explain the shape of Figure 7-10.(c) Differentiate
Define buffer capacity.
Which has the greater buffer capacity: (a) A mixture containing 0.100 mol of NH3 and 0.200 mol of NH4Cl(b) A mixture containing 0.0500 mol of NH3 and 0.100 mol of NH4Cl?
What mass of sodium glycolate should be added to 400.0 mL of 1.00 M glycolic acid to produce a buffer solution with a pH of 4.25?
What volume of 2.00 M NaOH must be added to 200.0 mL of 1.00 M glycolic acid to produce a buffer solution having a pH of 4.15?
Is the following statement true or false or both? Define your answer with equations, examples, or graphs. “A buffer maintains the pH of a solution constant.”
List several general properties of activity coefficients.
Explain why the activity coefficient for a neutral molecule is usually 1.
What is the numerical value of the activity coefficient of aqueous ammonia (NH3) at an ionic strength of 0.2?
Calculate the ionic strength of a solution that is(a) 0.025 M in FeSO4.(b) 0.25 M in (NH4)2CrO4.(c) 0.25 M in FeCl3 and 0.15 M in FeCl2.(d) 0.025 M in La(NO3)3 and 0.050 M in Fe(NO3)2.
Use Equation 8-5 to calculate the activity coefficient of(a) Fe3+ at μ 5 0.057.(b) Pb2+ at μ 5 0.026.(c) Ce4+ at μ 5 0.065.(d) Sn4+ at μ 5 0.040.
For a solution in which μ = 6.5 x 10-2, calculate K'sp for(a) AgSCN.(b) PbI2.(c) La(IO3)3.(d) MgNH4PO4.
The equilibrium constant for formation of CuCl2- is given byWhat is the solubility of CuCl in solutions having the following analytical NaCl concentrations:(a) 5.0 M?(b) 5.0 3 10-1 M?(c) 5.0 3 10-2
Use activities to calculate the molar solubility of Zn(OH)2 in(a) 0.0150 M KCl.(b) 0.0250 M K2SO4.(c) The solution that results when you mix 40.0 mL of 0.250 M KOH with 60.0 mL of 0.0250 M
Demonstrate how the sulfide ion concentration is related to the hydronium ion concentration of a solution that is kept saturated with hydrogen sulfide.
Calculate the concentration of CuS in a solution in which [H3O+] is held constant at (a) 2.0 x 10-1 M(b) 2.0 x 10-4 M.
A solution is 0.030 M in Na2SO4 and 0.040 M in NaIO3.To this is added a solution containing Ba2+.Assuming that no HSO4- is present in the original solution,(a) Which barium salt will precipitate
Using 1.0x 10-6 M as the criterion for quantitative removal, determine whether it is feasible to use(a) SO4 2- to separate Ba2+ and Sr2+ in a solution that is initially 0.030 M in Sr2+ and 0.15 M in
Define(a) Digestion.(b) Adsorption.(c) Reprecipitation.(d) Precipitation from homogeneous solution.(e) Counter-ion layer.(f) Mother liquor.(g) Supersaturation.
Define what constitutes a chelating agent.
How can the relative supersaturation be varied during precipitate formation?
Suggest a method by which Pb2+ can be precipitated homogeneously as PbS.
What is peptization, and how is it avoided?
Suggest a precipitation method for separation of K+ from Na+ and Li+.
Treatment of a 0.3500-g sample of impure potassium chloride with an excess of AgNO3 resulted in the formation of 0.3846 g of AgCl. Calculate the percentage of KCl in the sample.
The iodide in a sample that also contained chloride was converted to iodate by treatment with an excess of bromine:The unused bromine was removed by boiling; an excess of barium ion was then added to
The aluminum in a 2.200-g sample of impure ammonium aluminum sulfate was precipitated with aqueous ammonia as the hydrous Al2O3 . xH2O. The precipitate was filtered and ignited at 1000ºC to give
The addition of dimethylglyoxime, H2C4H6O2N2, to a solution containing nickel(II) ion gives rise to a precipitate:Nickel dimethylglyoxime is a bulky precipitate that is inconvenient to manipulate in
What mass of Cu(IO3)2 can be formed from 0.475 g of CuSO4 . 5H2O?
A 0.7812-g sample of impure Al2(CO3)3 decomposed with HCl; the liberated CO2 was collected on calcium oxide and found to weigh 0.04380 g. Calculate the percentage of aluminum in the sample.
The hydrogen sulfide in a 40.0-g sample of crude petroleum was removed by distillation and collected in a solution of CdCl2. The precipitated CdS was then filtered, washed, and ignited to CdSO4.
A 5.500-g sample of a pesticide was decomposed with metallic sodium in alcohol, and the liberated chloride ion was precipitated as AgCl. Express the results of this analysis in terms of percent DDT
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?
Titration of 50.00 mL of 0.04715 M Na2C2O4 required 39.25 mL of a potassium permanganate solution.Calculate the molar concentration of the KMnO4 solution. 2MNO4 + 5H2C,O, + 6H+ 2Mn?+ + 10CO,(g) + 8H20
The phosphorus in a 0.3019-g sample was precipitated as the slightly soluble (NH4)3PO4 . 12MoO3. This precipitate was filtered, washed, and then redissolved in acid. Treatment of the resulting
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
A 0.5002-g sample that assayed 96.4% Na2SO4 required 48.63 mL of a barium chloride solution. Reaction:Calculate the analytical molar concentration of BaCl2 in the solution. Ba?+ + So,?- → BaSO4(s)
Define(a) Millimole.(b) Titration.(c) Stoichiometric ratio.(d) Titration error.
The arsenic in a 1.203-g sample of a pesticide was converted to H3AsO4 by suitable treatment. The acid was then neutralized, and 40.00 mL of 0.05871 M AgNO3 was added to precipitate the arsenic
Write two equations that—along with the stoichiometric factor—form the basis for the calculations of volumetric titrations.
A 4.912-g sample of a petroleum product was burned in a tube furnace, and the SO2 produced was collected in 3% H2O2. Reaction:A 25.00-mL portion of 0.00873 M NaOH was introduced into the solution of
How many millimoles of solute are contained in(a) 2.00 L of 2.76 x 10-3 M KMnO4?(b) 250.0 mL of 0.0423 M KSCN?(c) 500.0 mL of a solution containing 2.97 ppm CuSO4?(d) 2.50 L of 0.352 M KCl?
What mass of solute in milligrams is contained in(a) 26.0 mL of 0.250 M sucrose (342 g/mol)?(b) 2.92 L of 5.23 x 10-4 M H2O2?(c) 673 mL of a solution that contains 5.76 ppm Pb(NO3)2 (331.20
Calculate the molar concentration of a solution that is 50.0% NaOH (w/w) and has a specific gravity of 1.52.
A 0.1475-M solution of Ba(OH)2 was used to titrate the acetic acid (60.05 g/mol) in a dilute aqueous solution. The following results were obtained.(a) Calculate the mean w/v percentage of acetic acid
A solution of Ba(OH)2 was standardized against 0.1215 g of primary-standard-grade benzoic acid, C6H5COOH (122.12 g/mol). An end point was observed after addition of 43.25 mL of base.(a) Calculate the
The following are three sets of data for the atomic mass of antimony from the work of Willard and McAlpine:(a) Determine the mean and the standard deviation for each data set.(b) Determine the 95%
(a) A 0.1527-g sample of primary-standard AgNO3 was dissolved in 502.3 g of distilled water. Calculate the weight molar concentration of Ag+ in this solution.(b) The standard solution described in
Four different fluorescence flow cell designs were compared to see if they were significantly different. The following results represented relative fluorescence intensities for four replicate
A solution was prepared by dissolving 367 mg of K3Fe(CN)6 (329.2 g/mol) in sufficient water to give 750.0 mL. Calculate(a) The molar analytical concentration of K3Fe(CN)6.(b) The molar concentration
The mishandling of a shipping container loaded with 850 cases of wine caused some of the bottles to break. An insurance adjuster proposed to settle the claim at 20.8% of the value of the shipment,
A coating that weighs at least 2.00 mg is needed to impart adequate shelf life to a pharmaceutical tablet. A random sampling of 200 tablets revealed that 16 failed to meet this requirement.(a) Use
What factors determine the mass of a gross sample?
What is the object of the sampling step in an analysis?
Sewage and industrial pollutants dumped into a body of water can reduce the dissolved oxygen concentration and adversely affect aquatic species. In one study, weekly readings are taken from the same
A 0.005-g sample of a rock is to be analyzed, and iron is to be determined at the ppm level. Determine the type of analysis and type of constituent.
Determination of phosphorous in blood serum gave results of 4.40, 4.42, 4.60, 4.48, and 4.50 ppm P. Determine whether the 4.60 ppm result is an outlier or should be retained at the 95% confidence
Analysis of several plant-food preparations for potassium ion yielded the following data:The preparations were randomly drawn from the same population.(a) Find the mean and standard deviation s for
Before agreeing to the purchase of a large order of solvent, a company wants to see conclusive evidence that the mean value of a particular impurity is less than 1.0 ppb. What hypotheses should be
Nine samples of illicit heroin preparations were analyzed in duplicate by a gas chromatographic method. The samples can be assumed to have been drawn randomly from the same population. Pool the
To test the quality of the work of a commercial laboratory, duplicate analyses of a purified benzoic acid (68.8% C, 4.953% H) sample were requested. It is assumed that the relative standard deviation
In a volumetric determination of an analyte A, the data obtained and their standard deviations are as follows:From the data, find the coefficient of variation of the final result for the % A that is

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