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Transcript
Министерство образования и науки Российской Федерации
Южно-Уральский государственный университет
Химический факультет
Ш143.21-9
Д182
Е.И.Данилина
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ
Модуль 3
АНАЛИТИЧЕСКАЯ ХИМИЯ
Учебное пособие
Челябинск
Издательский центр ЮУрГУ
2010
ББК Ш143.21-923
УДК 543(075.8)
Одобрено
учебно-методической комиссией химического факультета
Рецензенты
Балыкин В.П., д-р хим. наук, профессор кафедры аналитической и физической
химии Челябинского государственного университета
Толчев А.В., д-р хим. наук, профессор, зав. кафедрой общетехнических
дисциплин Челябинского государственного педагогического университета
Д182
Данилина, Е.И.
Химия на английском языке. Модуль 3. Аналитическая химия: учебное
пособие. – Челябинск: Издательский центр ЮУрГУ, 2010. – 40 с.
Учебное пособие составлено на английском языке по материалам
британских, канадских и американских учебников по аналитической
химии для университетов. Пособие предназначено для практических
занятий и самостоятельной работы студентов. В учебном пособии
предложены качественные вопросы и расчетные задачи, охватывающие
основные темы базового курса аналитической химии. В приложениях
приведены необходимые справочные материалы для численного решения
задач и их устного чтения.
Пособие предназначено для студентов 3 курса химического
факультета.
ББК Ш143.21-923
УДК 54(075.8)
© Издательский центр ЮУрГУ, 2010
2
CONTENTS
1. Evaluating Analytical Data…………………………………………………… 3
2. Gravimetric Methods of Analysis……………………………………………..12
3. Titrimetric Methods of Analysis………………………………………………17
4. Instrumental Analysis………………………………………………………….25
References……………………………………………………………………….. 31
Appendix 1. Periodic Table of Chemical Elements……………………………....32
Appendix 2. Elements and Electronegative Components………………………...34
Appendix 3. Acids and Anions……………………………………………………37
Appendix 4. Critical Values for t-Test for Chosen Confidence Intervals…..…….38
Appendix 5. Critical Values for Q-Test………………………………………….. 38
Appendix 6. F-Table for Two-Tailed Test (95% Confidence Level)……………..39
3
1. EVALUATING ANALYTICAL DATA
1.1. Give the SI metric prefix that corresponds to each of the following:
a) 1000;
d) 106;
b) 10–3;
e) 102;
c) 10–9;
f) 0.000001.
1.2. Figure out the relationship between units.
a) Convert 360 s to ms.
b) Convert 4800 g to kg.
c) Convert 5600 dm to m.
d) Convert 72 g to mg.
1.3. Figure out the relationship between units.
a) Convert 245 ms to s.
b) Convert 5 m to cm.
c) Convert 6800 cm to m.
d) Convert 2500 kg to Mg.
1.4. Express each of the following quantities in the unit listed in parentheses.
a) 3.01 g (cg);
d) 0.2 L (mL);
b) 6200 m (km);
e) 0.13 cal/g (kcal/g);
–7
c) 6.24⋅10 g (μg);
f) 3.21 g/cm3 (kg/m3).
1.5. The density of gold is 19.3 g/mL. What is gold's density in decigrams per liter?
1.6. Write each of the following as an ordinary decimal number.
a) 6.235⋅10–2;
e) 9.71⋅104;
f) 9.71⋅10–4;
b) 7.229⋅103;
g) 4.221⋅106;
c) 5.001⋅10–6;
d) 8.621⋅102;
h) 1.22⋅10–3.
1.7. Express each of the following as an ordinary decimal number.
e) 9.999⋅103;
a) 4.83⋅102;
f) 1.016⋅10–5;
b) 7.221⋅10–4;
g) 1.016⋅105;
c) 6.10⋅100;
d) 9.11⋅10–8;
h) 4.11⋅10–1.
1.8. For each of the following numbers, if the number is rewritten in standard scientific
(exponential) notation, what will be the value of the exponent (for the power of 10)?
a) 0.000067;
c) 1/10000;
b) 9 331 442;
d) 163.1⋅102.
4
1.9. Write each of the following numbers in standard scientific (exponential) notation.
e) 0.0251⋅104;
a) 142.3⋅103;
f) 97522⋅10–3;
b) 0.0007741⋅10–5;
g) 0.000009752⋅106;
c) 22.7⋅105;
h) 44252⋅104.
d) 6272⋅10–5;
1.10. Express the following quantities in standard scientific (exponential) notation.
Convert into convenient units of measurement.
a) 360 000 s;
c) 5060 s;
b) 0.000 054 s;
d) 89 000 000 000 s.
1.11. Express the following quantities in standard scientific (exponential) notation.
Convert into convenient units of measurement.
a) 700 m;
e) 0.0054 kg;
b) 38 000 m;
f) 0.000 006 87 kg;
c) 4 500 000 m;
g) 0.000 000 076 kg;
d) 685 000 000 000 m; h) 0.000 000 000 8 kg.
1.12. The diameter of a proton is 2⋅10–15 meters. What is this diameter in nanometers?
1.13. The mass of an electron is 9.1093897⋅10–31 kg. What is this mass in femtograms?
1.14. The diameter of typical bacteria cells is 0.00032 centimeters. What is this diameter
in micrometers?
1.15. A piece of Styrofoam has a mass of 88.978 g and a volume of 2.9659 L. What is
its density in g/mL?
1.16. The density of blood plasma is 1.03 g/mL. A typical adult has about 2.5 L of
blood plasma. What is the mass in kilograms of this amount?
1.17. When you are at rest, your heart pumps about 5.0 liters of blood per minute. You
brain gets about 15% by volume of your blood. What volume of blood in liters is
pumped through your brain in 1.0 hour of rest?
1.18. Indicate how many significant figures are in each of the following numbers.
a) 903;
c) 1.0903;
e) 0.09030;
b) 0.903;
d) 0.0903;
f) 9.03⋅102.
1.19. Round each of the following to three significant figures.
a) 0.89377;
c) 0.89350;
e) 0.08907;
b) 0.89328;
d) 0.8997;
f) 0.008911.
5
1.20. Determine the number of significant figures in each measurement. Convert into
convenient units with the same number of significant figures.
a) 580.0 L;
e) 0.049 450 s;
b) 820 400.0 kg;
f) 0.000 482 mL;
5
g) 3.1587⋅10–4 g;
c) 1.0200⋅10 mg;
d) 87 000 mL;
h) 0.0084 kg.
1.21. Round all numbers to four significant figures. Express the quantities in convenient
units of measurement.
a) 84 791 mg;
c) 256.75 cm;
e) 0.015317 kg;
b) 38.5432 g;
d) 4.9356 m;
f) 11.5367 g/mL.
1.22. Round each of the following to the stated number of significant figures.
a) The atomic mass of carbon to four significant figures.
b) The atomic mass of oxygen to three significant figures.
c) Avogadro's number to four significant figures.
d) Faraday's constant to three significant figures.
1.23. Round all numbers to four significant figures. Write the answers in scientific
notation.
a) 136 758 kg;
c) 21.7658 g;
e) 0.000 548 18 g;
b) 2.0145 mL;
d) 0.15366 m;
f) 308 659 000 mm.
1.24. Complete the following addition and subtraction problems. Round off the answers
when necessary.
a) 43.2 cm + 51.0 cm – 48.7 cm;
b) 258.3 kg – 257.11 kg + 253 kg;
c) 0.0487 mg + 0.05834 mg – 0.00483 mg;
d) 4.32⋅103 cm – 0.61⋅102 cm.
1.25. Complete the following multiplication and division problems without the use of a
calculator.
a) 1012 / 109;
d) 10–8 / 105;
e) 10–11 ⋅ 108;
b) 1014 ⋅ 105;
f) 1010 ⋅ 103 / 10–9.
c) 1017 ⋅ 106 / 103;
1.26. Complete the following calculations. Round off the answers to the correct number
of significant figures.
a) 24 m ⋅ 3.26 m;
e) 1.23 m ⋅ 2.0 m;
b) 4.84 m / 2.4 s;
f) 102.4 m / 51.2 s;
c) 120 m ⋅ 0.10 m;
g) 53.0 m ⋅ 1.53 m;
d) 60.2 m / 20.1 s;
h) 168 m / 58 s.
6
1.27. Complete the following calculations. Round off the answers to the correct number
of significant figures.
d) 8.50⋅10–7 × 2.2⋅103;
a) 9.5⋅105 × 8⋅109;
b) 6.02⋅1023 × 6.0⋅103; e) 7.203⋅109 × 10–4;
f) 9.674⋅10–3 × 2.000⋅10–8.
c) 2.755⋅104 × 5⋅106;
1.28. Report results for the following calculations to the correct number of significant
figures:
a) 4.591 + 0.2309 + 67.1 =
b) 313 – 273.15 =
c) 712 ⋅ 8.6 =
d) 1.43 / 0.026 =
e) (8.314 ⋅ 298) / 96485 =
f) log(6.53⋅10–5) =
g) 10–7.14 =
h) (6.51⋅10–5) (8.14⋅10–9) =
1.29. Round the answers to each of the following problems to the correct number of
significant figures.
a) 7.31⋅104 + 3.23⋅103 =
b) 8.54⋅10–3 – 3.41⋅10–4 =
c) 4.35 dm ⋅ 2.34 dm ⋅ 7.35 dm =
d) 4.78 cm + 3.218 cm + 5.82 cm =
e) 3.40 mg + 0.84 mg + 0.645 mg =
f) 45 m ⋅ 72 m ⋅ 132 m =
g) 38736 km / 4784 km =
1.30. The following masses were recorded for 12 different U.S. quarters (all given in
grams):
5.683
5.549
5.548
5.552
5.620
5.536
5.539
5.684
5.551
5.552
5.554
5.632
Report the mean, median, range, standard deviation, and variance for these data.
1.31. Shown in the following rows are results for the determination of acetaminophen
(in milligrams) in ten separate tablets.
224.3
240.4
246.3
239.4
253.1
261.7
229.4
255.5
235.5
249.7
Report the mean, median, range, standard deviation, and variance for these data.
1.32. When a new method for determining the amount of morphine hydrochloride in
tablets has been developed, the results, in milligrams, for several tablets containing
different nominal dosages:
7
100-mg
60-mg
30-mg
10-mg
tablets
tablets
tablets
tablets
99.17
54.21
28.51
9.06
94.31
55.62
26.25
8.83
95.92
57.40
25.92
9.08
94.55
57.51
28.62
93.83
52.59
24.93
For each dosage, calculate the mean and standard deviation for the milligrams of
morphine hydrochloride per tablet.
1.33. The quantitative determination of chromium in high-alloy steels by a
potentiometric titration of Cr6+ led to the following results (% m/m Cr) for the analysis
of a single reference steel.
16.968
16.922
16.840
16.883
16.887
16.977
16.857
16.728
Calculate the mean, the standard deviation, and the 95% confidence interval about the
mean.
1.34. The molar mass (M) of a gas can be determined using the ideal gas law:
M = gRT / PV,
where g is the mass in grams, R is the gas constant, T is the temperature in kelvins, P is
the pressure in atmospheres, and V is the volume in liters.
In a typical analysis the following data are obtained (with estimated uncertainties
in parentheses): g = 0.118 (±0.002); R = 0.082056 (±0.000001); T = 298.2 (±0.1); P =
0.724 (±0.005); V = 0.250 (±0.005). What is the compound’s molar mass and its
estimated uncertainty?
1.35. Which of the following is the best way to dispense 100.0 mL of a reagent: (a) use
a 50-mL pipette twice; (b) use a 25-mL pipette four times; or (c) use a 10-mL pipette
ten times?
1.36. What is the smallest mass that can be measured on an analytical balance with a
tolerance of ±0.1 mg, such that the relative error is less than 0.1%?
1.37. Hydroscopic materials often are measured by the technique of weighing by
difference. In this technique the material is placed in a sealed container and weighed. A
portion of the material is removed, and the container and the remaining material are
reweighed. The difference between the two masses gives the amount of material that
was sampled. A solution of a hydroscopic material with a gram formula weight of
121.34 (±0.01) was prepared in the following manner. A sample of the compound and
its container has a mass of 23.5811 g. A portion of the compound was transferred to a
100-mL volumetric flask and diluted to volume. The mass of the compound and
container after the transfer is 22.1559 g. Calculate the molarity of the solution, and
estimate its uncertainty by a propagation of uncertainty calculation.
8
1.38. A standard solution of Mn2+ was prepared by dissolving 0.250 g of Mn in 10 mL
of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was
quantitatively transferred to a 100-mL volumetric flask and diluted to volume with
distilled water. A 10-mL aliquot of the solution was pipeted into a 500-mL volumetric
flask and diluted to volume. Express the concentration of Mn in parts per million, and
estimate uncertainty by a propagation of uncertainty calculation. Would the uncertainty
in the solution’s concentration be improved by using a pipette to measure the HNO3,
instead of a graduated cylinder?
1.39. A new analytical method for measuring trace levels of atmospheric gases has been
developed. The analysis of a sample containing 40.0 parts per thousand (ppt) 2chloroethylsulfide yielded the following results: 43.3; 34.8; 31.9; 37.8; 34.4; 31.9; 42.1;
33.6; 35.3. Determine whether there is a significant difference between the experimental
mean and the expected value at α = 0.05.
1.40. To test a spectrophotometer for its accuracy, a solution of 60.06 ppm K2Cr2O7 in
5.0 mM H2SO4 is prepared and analyzed. This solution has a known absorbance of
0.640 at 350.0 nm in a 1.0-cm cell when using 5.0 mM H2SO4 as a reagent blank.
Several aliquots of the solution are analyzed with the following results: 0.639; 0.638;
0.640; 0.639; 0.640; 0.639; 0.638. Determine whether there is a significant difference
between the experimental mean and the expected value at α = 0.01.
1.41. Analysts suggested the use of radioactive isotopes as a means of dating sediments
collected from the bottom of lakes. To verify this method they analyzed a 208Po standard
known to have an activity of 77.5 decays/min, obtaining the following results:
77.09
75.37
72.42
76.84
77.84
76.69
78.03
74.96
77.54
76.09
81.12
75.75
Determine whether there is a significant difference between the mean and the expected
value at α = 0.05.
1.42. A 2.6540-g sample of an iron ore known to contain 53.51% m/m Fe is dissolved in
a small portion of concentrated HCl and diluted to volume in a 250-mL volumetric
flask. A spectrophotometric method is used to determine the concentration of iron in
this solution, yielding results of 5840, 5770, 5650, and 5660 ppm. Determine whether
there is a significant difference between the experimental mean and the expected value
(α = 0.05).
1.43. In order to release mercury form coal fly ash several reagents for digesting
samples have been studied. All concentrations are given as nanograms of Hg per gram
of sample. Results obtained with HNO3 and with a mixture of HNO3 and HCl are shown
here.
HNO3:
161 165 160 167 166
HNO3–HCl:
159 145 140 147 143 156
Determine whether there is a significant difference between these methods at α = 0.05.
9
1.44. Following is a summary of atmospheric air analysis results with SO2
concentrations reported in microliters per cubic meter.
The standard method: 21.62; 22.20; 24.27; 23.54; 24.25; 23.09; 21.02.
A new method:
21.54; 20.51; 22.31; 21.30; 24.62; 25.72; 21.54.
Using an appropriate statistical test, determine whether there is any significant
difference between the standard and new methods at α = 0.05.
1.45. The accuracy of a spectrophotometer can be checked by measuring absorbances
for a series of standard dichromate solutions that can be obtained in sealed cuvettes
from the National Institute of Standards and Technology. Absorbances are measured at
257 nm and compared with the accepted values. The results obtained when testing a
newly purchased spectrophotometer are shown here. Determine if the tested
spectrophotometer is accurate at α = 0.05.
Standard:
1
2
3
4
5
Measured absorbance: 0.2872
0.5773
0.8674
1.1623
1.4559
Accepted absorbance: 0.2871
0.5760
0.8677
1.1608
1.4565
1.46. Using X-ray diffraction, analysts developed a new method for determining the
mass percent of kalonite in complex clay minerals. To test the method, nine samples
containing known amounts of kalonite were prepared and analyzed. The results (as %
m/m kalonite) are shown.
Actual:
5.0 10.0 20.0 40.0 50.0 60.0 80.0 90.0 95.0.
Found:
6.8 11.7 19.8 40.5 53.6 61.7 78.9 91.7 94.7.
Evaluate the accuracy of the method at α = 0.05.
1.47. The concentration of Fe3+ in human serum samples was determined by a proposed
method and the standard method. Following are the results, with concentrations in
micromoles/L.
Sample Proposed Method Standard Method
1
8.25
8.06
2
9.75
8.84
3
9.75
8.36
4
9.75
8.73
5
10.75
13.13
6
11.25
13.65
7
13.88
13.85
8
14.25
13.43
Determine whether there is a significant difference between the two methods (α = 0.05).
1.48. A given analytical test was performed five times. The results of the analysis are
represented by the following values: 37.23, 32.91, 45.38, 35.22, and 41.81%. Would
you say that these results are precise? Can you say that they are accurate? Explain both
answers.
10
1.49. A given analytical test was performed five times. The results of the analysis are
represented by the following values: 6.738, 6.738, 6.737, 6.739, and 6.738%. Suppose
the correct answer to the analysis is 6.923%. What can you say about the precision and
accuracy?
1.50. A series of eight absorbance measurements using an atomic absorption
spectrophotometer are as follows: 0.855, 0.836, 0.848, 0.870, 0.859, 0.841, 0.861, and
0.852. According to the instrument manufacturer, the precision of the absorbance
measurements using this instrument should not exceed 1% relative standard deviation.
Does it in this case?
1.51. Ten laboratories were asked to determine the concentration of an analyte A in
three standard test samples. Following are the results, in parts per million.
Laboratory Sample 1 Sample 2 Sample 3
1
22.6
13.6
16.0
2
23.0
14.2
15.9
3
21.5
13.9
16.3
4
21.9
13.9
16.9
5
21.3
13.5
16.7
6
22.1
13.5
17.4
7
23.1
13.9
17.5
8
21.7
13.5
16.8
9
22.2
12.9
17.2
10
21.7
13.8
16.7
Determine if there are any potential outliers in Sample 1, Sample 2, or Sample 3 at a
significance level of α = 0.05.
1.52. Analyzing apatite, a student got the results of P2O5 contents, in % m/m: 35.11;
35.14; 35.18; 35.21; 35.42. Should the student include all the results while calculating
the mean and 95% confidence interval?
1.53. Gravimetric determination of sulfate ion yielded the results, expressed in % SO3:
15.51; 15.45; 15.48; 15.58; 16.21. The last result looks like a potential outlier. Is it true?
For what significance level?
1.54. An acidic solution was studied by the potentiometric method with the use of a
glass electrode. The results of pH measurements are the following: 5.48; 5.45; 5.30;
5.50; 5.55. Determine whether the smallest value can be classified as an outlier at a
significance level of α = 0.05.
11
2. GRAVIMETRIC METHODS OF ANALYSIS
2.1. Consider the analysis of the water from a lake for suspended solid particles. A
sample of the water was filtered through a preweighed filter to separate the suspended
solids from the water. The following data were recorded:
Volume of water used:
100 mL
Weight of empty filter:
11.6734 g
Weight of filter with solids:
11.7758 g
What is the concentration in milligrams per liter of suspended solids in the water?
2.2. Consider the analysis of a 100.0-mL sample of wastewater for total solids and
settleable solids. If the evaporating dish containing the dried sample weighs 38.1193 g,
and the empty evaporating dish weighs 37.0209 g, what is the concentration of total
solids in milligrams per liter in this sample? If, after the suspended solids had settled,
100.0 mL of the resulting sample was again tested for solids, with the empty
evaporating dish weighing 37.3884 g and the evaporating dish containing the dried
sample weighing 37.8929 g, what is the concentration of settleable solids in milligrams
per liter?
2.3. Consider the analysis of a salt–sand mixture. If the mixture contained in a beaker
was treated with sufficient water to dissolve the salt, and weight of mixture equaled
5.3502 g, while weight of sand isolated from mixture after filtering and drying was
4.2034 g, what are the percents of both the salt and sand in the mixture?
2.4. What is the gravimetric factor, expressed to four significant figures, for each of the
following gravimetric analysis examples?
Substance Sought
Ag
SO3
Ag2O
Na3PO4
Substance Weighed
AgBr
BaSO4
AgCl
Mg2P2O7
Substance Sought
Pb3O4
SiF4
Co3O4
Bi2S3
Substance Weighed
PbCrO4
CaF2
Co2O3
Bi2O3
2.5. What is the gravimetric factor:
a) for obtaining the weight of Ag2CrO4 from the weight of AgCl?
b) if one is calculating the percent of Na2SO4 in a mixture when the weight of
Na3PO4 is measured?
c) when converting the weight of Hg to the weight of Hg2Cl2?
2.6. What is the gravimetric factor that must be used in each of the following
experiments?
a) The weight of Mg2P2O7 is known and the weight of MgO is to be calculated.
b) The weight of Fe3O4 is to be converted to the weight of FeO.
c) The weight of Mn3O4 is to be determined from the weight of Mn2O3.
12
2.7. If a technician wishes to prepare a solution containing 55.3 mg of barium, how
many grams of barium chloride dihydrate does he or she need to weigh?
2.8. What weight of K2SO4 is equivalent to 0.6603 g of K3PO4?
2.9. What weight of P2O5 is equivalent to 0.6603 g of P?
2.10. What is the percent of K2CrO4 in a sample that weighed 0.7193 g if the weight of
the Cr2O3 precipitate derived from the sample was 0.1384 g?
2.11. The gravimetric factor for converting the weight of BaCO3 to Ba is 0.6959. If the
weight of BaCO3 derived from a sample was 0.2644 g, what weight of Ba was in this
sample?
2.12. If 0.9110 g of a sample of silver ore yielded 0.4162 g of AgCl in a gravimetric
experiment, what is the percentage of Ag in the ore?
2.13. Given the following data, what is the percent S in the sample?
Weight of weighing bottle before dispensing sample:
5.3403 g
Weight of weighing bottle after dispensing sample:
4.8661 g
Weight of crucible with BaSO4 precipitate:
19.3428 g
Weight of empty crucible:
18.7155 g.
2.14. Given the following data, what is the percent Fe in the sample?
Weight of weighing bottle before dispensing sample:
3.5719 g
Weight of weighing bottle after dispensing sample:
3.3110 g
Weight of crucible with Fe2O3 precipitate:
18.1636 g
Weight of empty crucible:
18.0021 g.
2.15. Nickel can be precipitated with dimethylglyoxime (DMG) according to the
following reaction:
Ni2+ + 2 HDMG → Ni(DMG)2 + 2 H+
If 2.0116 g of a nickel-containing substance is dissolved and the nickel precipitated as
above so that the Ni(DMG)2 precipitate weighs 2.6642 g, what is the percentage of
nickel in the substance? The molar mass of Ni(DMG)2 is 288.92 g/mol.
2.16. Imagine an experiment in which the percentage of manganese, Mn, in a
manganese ore is to be determined by gravimetric analysis. If 0.8423 g of the ore
yielded 0.3077 g of Mn3O4 precipitate, what is the percent Mn in the ore?
2.17. A sample of an impure iron ore is believed to be approximately 55% m/m Fe. The
amount of Fe in the sample is to be determined gravimetrically by isolating it as Fe2O3.
How many grams of sample should be taken to ensure that approximately 1 g of Fe2O3
will be isolated?
13
2.18. The concentration of arsenic in an insecticide can be determined gravimetrically
by precipitating it as MgNH4AsO4. The precipitate is ignited and weighed as Mg2As2O7.
Determine the % m/m As2O3 in a 1.627-g sample of insecticide that yields 106.5 mg of
Mg2As2O7.
2.19. After preparing a sample of alum, K2SO4•Al2(SO4)3•24H2O, a student determined
its purity gravimetrically. A 1.2931-g sample was dissolved and the aluminum
precipitated as Al(OH)3. The precipitate was collected by filtration, washed, and ignited
to Al2O3, yielding 0.1357 g. What is the purity of the alum preparation?
2.20. To determine the amount of iron in a dietary supplement, a random sample of 15
tablets weighing a total of 20.505 g was ground into a fine powder. A 3.116-g sample of
the powdered tablets was dissolved and treated to precipitate the iron as Fe(OH)3. The
precipitate was collected, rinsed, and ignited to a constant weight as Fe2O3, yielding
0.355 g. Report the iron content of the dietary supplement as g FeSO4⋅7H2O per tablet.
2.21. A 1.4639-g sample of limestone was analyzed for Fe, Ca, and Mg. The iron was
determined as Fe2O3, yielding 0.0357 g. Calcium was isolated as CaSO4, yielding a
precipitate of 1.4058 g, and Mg was isolated as 0.0672 g of Mg2P2O7. Report the
amount of Fe, Ca, and Mg in the limestone sample as % m/m Fe2O3, % m/m CaO, and
% m/m MgO.
2.22. The number of ethoxy groups (CH3CH2O–) in an organic compound can be
determined by the following sequence of reactions:
R(OCH2CH3)x + x HI → R(OH)x + x CH3CH2I
CH3CH2I + Ag+ + H2O → AgI(s) + CH3CH2OH.
A 36.92-mg sample of an organic compound with an approximate molecular weight of
176 was treated in this fashion, yielding 0.1478 g of AgI. How many ethoxy groups are
there in each molecule?
2.23. A 516.7-mg sample containing a mixture of K2SO4 and (NH4)2SO4 was dissolved
in water and treated with BaCl2, precipitating the SO42– as BaSO4. The resulting
precipitate was isolated by filtration, rinsed free of impurities, and dried to a constant
weight, yielding 863.5 mg of BaSO4. What is the % m/m K2SO4 in the sample?
2.24. The amount of iron and manganese in an alloy can be determined by precipitating
the metals with 8-hydroxyquinoline, C9H7NO. After weighing the mixed precipitate, the
precipitate is dissolved and the amount of 8-hydroxyquinoline determined by another
method. In a typical analysis, a 127.3-mg sample of an alloy containing iron,
manganese, and other metals was dissolved in acid and treated with appropriate
masking agents to prevent an interference from other metals. The iron and manganese
were precipitated and isolated as Fe(C9H6NO)3 and Mn(C9H6NO)2, yielding a total mass
of 867.8 mg. The amount of 8-hydroxyquinolate in the mixed precipitate was
determined to be 5.276 mmol. Calculate the % m/m Fe and % m/m Mn in the alloy.
14
2.25. A 0.8612-g sample of a mixture consisting of NaBr, NaI, and NaNO3 was
analyzed by adding AgNO3 to precipitate the Br– and I–, yielding a 1.0186-g mixture of
AgBr and AgI. The precipitate was then heated in a stream of Cl2, converting it to
0.7125 g of AgCl. Calculate the % m/m NaNO3 in the sample.
2.26. The earliest determinations of elemental atomic masses were accomplished
gravimetrically. In determining the atomic mass of manganese, a carefully purified
sample of MnBr2 weighing 7.16539 g was dissolved and the Br– precipitated as AgBr,
yielding 12.53112 g. What is the atomic mass for Mn if the atomic masses for Ag and
Br are taken to be 107.868 and 79.904, respectively?
2.27. Two methods have been proposed for the analysis of sulfur in impure samples of
pyrite, FeS2. Sulfur can be determined in a direct analysis by oxidizing it to SO42– and
precipitating as BaSO4. An indirect analysis is also possible if the iron is precipitated as
Fe(OH)3 and isolated as Fe2O3. Which of these methods will provide a more sensitive
determination for sulfur?
2.28. A sample of impure pyrite known to be approximately 90–95% m/m FeS2 is to be
analyzed by oxidizing the sulfur to SO42– and precipitating as BaSO4. How many grams
of the sample must be taken if a minimum of 1 g of BaSO4 is desired?
2.29. A series of samples consisting of any possible combination of KCl, NaCl, and
NH4Cl is to be analyzed by adding AgNO3 to precipitate AgCl. What is the minimum
volume of 5% m/v AgNO3 necessary to completely precipitate the chloride in any 0.5-g
sample?
2.30. A polymer’s ash content is determined by placing a weighed sample in a Pt
crucible that has been previously brought to a constant weight. The polymer is melted
under gentle heating from a Bunsen burner until the volatile vapor ignites. The polymer
is allowed to burn until only a noncombustible residue remains. The residue is then
brought to constant weight at 800 °C in a muffle furnace. The following data were
collected during the analysis of two samples of a polymer resin:
Experiments
m (g)
crucible
replicate 1
replicate 2
replicate 3
19.1458
15.9193
15.6992
replicate 1
replicate 2
replicate 3
19.1457
15.6991
15.9196
m (g)
crucible + polymer
Polymer A
21.2287
17.9522
17.6660
Polymer B
21.0693
17.8273
17.9037
15
m (g)
crucible + ash
19.7717
16.5310
16.2909
19.7187
16.3327
16.5110
a) Determine the average and standard deviation for the % m/m ash of each
polymer resin.
b) Is there any evidence at α = 0.05 for a significant difference between the two
polymer resins?
2.31. The concentration of airborne particulates in an industrial workplace was
determined by pulling the air through a single-stage air sampler equipped with a glass
fiber filter. The air was sampled for 20 min at a rate of 75 m3/h. At the end of the
sampling period the glass fiber filter was found to have increased in mass by 345.2 mg.
What is the concentration of particulates in the air sample in milligrams per cubic meter
and in milligrams per liter?
2.32. The fat content of potato chips can be determined indirectly by weighing a sample
before and after extracting the fat with supercritical CO2. The following data were
obtained for the analysis of one sample of potato chips:
Sample Number
1
2
3
4
5
Initial Sample Mass (g)
1.1661
1.1723
1.2525
1.2280
1.2837
Final Sample Mass (g)
0.9253
0.9252
0.9850
0.9562
1.0119
a) Determine the average fat content (% m/m) for this sample of potato chips.
b) This sample of potato chips is known to have a fat content of 22.7% m/m. Is
there any evidence for a determinate error in the data at α = 0.05?
2.33. Find a real-world gravimetric analysis in a methods book, in a journal, or on a
website and report on the details of the procedure according to the following scheme:
a) Title.
b) General information, including type of material examined, name of the analyte,
sampling procedures, and sample preparation procedures.
c) Specifics, including type of equipment used, details of exactly how the analyte
is separated from its matrix (oven temperatures, filtering method and material, etc.),
and, if chemical reaction or precipitation is required, the chemical equation for the
reaction, what the precipitating agent is, and how prepared.
d) Data handling and reporting.
e) References.
16
3. TITRIMETRIC METHODS OF ANALYSIS
3.1. What is the molarity of the following?
a) 0.694 mol dissolved in 3.55 L of solution.
b) 2.19 mol of NaCl dissolved in 700.0 mL of solution.
c) 0.3882 g of KCl dissolved in 0.5000 L of solution.
d) 1.003 g of CuSO4⋅5H2O dissolved in 250.0 mL of solution.
e) 30.00 mL of 6.0 M NaOH diluted to 100.0 mL of solution.
f) 0.100 L of 12.0 M HCl diluted to 500.0 mL of solution.
3.2. What is the equivalent weight of both reactants in each of the following?
a) NaOH + HCl → NaCl + H2O
b) 2 NaOH + H2SO4 → Na2SO4 + 2 H2O
c) 2 HCl + Ba(OH)2 → BaCl2 + 2 H2O
d) 3 NaOH + H3PO4 → Na3PO4 + 3 H2O
e) 2 HCl + Mg(OH)2 → MgCl2 + 2 H2O
f) 2 NaOH + H3PO4 → Na2HPO4 + 2 H2O
g) NaOH + Na2HPO4 → Na3PO4 + H2O
h) NaOH + H3PO4 → NaH2PO4 + H2O
i) Na2CO3 + 2 HCl → 2 NaCl + H2CO3
3.3. Calculate the normality of the following solutions:
a) 0.238 equivalents of an acid dissolved in 1.500 L of solution.
b) 1.29 mol of sulfuric acid dissolved in 0.5000 L of solution used for the
following reaction:
H2SO4 + 2 NaOH → Na2SO4 + 2 H2O
c) 0.904 mol of H3PO4 dissolved in 250.0 mL of solution used for the following
reaction:
H3PO4 + 3 KOH → K3PO4 + 3 H2O
d) 0.827 mol of Al(OH)3 dissolved in 0.2500 L of solution used for the following
reaction:
3 HCl + Al(OH)3 → AlCl3 + 3 H2O
e) 1.38 g of KOH dissolved in 500.0 mL of solution used for the chemical
reaction in part (c) above.
3.4. An H3PO4 solution is to be used to titrate an NaOH solution as in the equation in
the following reaction: H3PO4 + 2 KOH → KH2PO4 + 2 H2O. If the normality of the
H3PO4 solution is 0.2411 N, what is its molarity?
3.5. How many milliliters of a NaH2PO4 solution, prepared by dissolving 0.384 g in
500.0 mL of solution, are needed to prepare 1.000 L of a 0.00200 N solution given the
following reaction?
NaH2PO4 + Ca(OH)2 → CaNaPO4 + 2 H2O
17
3.6. Tell how you would prepare each of the following:
a) 500.0 mL of 0.20 N KH2PO4 used for the following reaction:
KH2PO4 + 2 NaOH → KNa2PO4 + 2 H2O
b) 500.0 mL of 0.11 N H2SO4 from concentrated H2SO4 (18.0 M) used for the
following reaction:
H2SO4 + Ca(OH)2 → CaSO4 + 2 H2O
c) 750.0 mL of 0.11 N Ba(OH)2 from pure solid Ba(OH)2 given the following
reaction:
2 Na2HPO4 + Ba(OH)2 → Ba(Na2PO4)2 + 2 H2O
d) 200.0 mL of a 0.15 N solution of the base in the following reaction:
2 HBr + Na2CO3 → 2 NaBr + H2O + CO2
e) 700.0 mL of a 0.25 N solution of the acid in the following reaction:
2 NaHCO3 + Mg(OH)2 → Mg(NaCO3)2 + 2 H2O
f) 700.0 mL of a 0.30 N solution of Ba(OH)2 from a 15.0 N solution of Ba(OH)2
used for the following reaction:
2 H3PO4 + Ba(OH)2 → Ba(H2PO4)2 + 2 H2O
g) 300.0 mL of 0.15 N solution of H3PO4 from concentrated H3PO4 (15 M) used
for the following reaction:
H3PO4 + Al(OH)3 → AlPO4 + 3 H2O
3.7. Suppose 0.7114 g of potassium hydrogen phthalate was used to standardize a
Mg(OH)2 solution, as in the following reaction:
Mg(OH)2 + 2 KHC8H4O4 → Mg(KC8H4O4)2 + 2 H2O
If 31.18 mL of Mg(OH)2 was needed, what is the molarity of Mg(OH)2?
3,8. A NaOH solution was standardized against a H3PO4 solution, as in the following
reaction:
H3PO4 + 3 NaOH → Na3PO4 + 3 H2O
If 25.00 mL of 0.1427 M H3PO4 required 40.07 mL of NaOH, what is the molarity of
NaOH?
3.9. A solution of KOH is standardized with primary standard potassium hydrogen
phthalate (KHC8H4O4). If 0.5480 g of the standard compound exactly reacted with
25.41 mL of the KOH solution, what is the molarity of KOH?
3.10. What is the normality of a solution of HCl, 35.12 mL of which was required to
titrate 0.4188 g of primary standard Na2CO3?
2 HCl + Na2CO3 → 2 NaCl + CO2 + H2O
3.11. What is the normality of a solution of sulfuric acid that was used to titrate a
0.1022 N solution of KOH, as in the following reaction, if 25.00 mL of the base was
exactly neutralized by 29.04 mL of the acid?
H2SO4 + 2 KOH → K2SO4 + 2 H2O
18
3.12. Primary standard tris-(hydroxymethyl)amino methane, also known as THAM or
TRIS (M = 121.14 g/mol), is used to standardize a hydrochloric acid solution. Suppose
0.4922 g of THAM is used and 23.45 mL of HCl is needed to neutralize it, what is the
normality of HCl?
(HOCH2)3CNH2 + HCl → (HOCH2)3CNH3+Cl–
3.13. What is the titer (expressed in milligrams per milliliter) of a solution of disodium
dihydrogen ethylenediaminetetraacetate (EDTA) with respect to calcium carbonate if
17.29 mL of it was needed to titrate 0.0384 g of calcium carbonate?
3.14. What is the percent of K2HPO4 in a sample when 46.79 mL of 0.04223 M
Ca(OH)2 exactly neutralizes 0.9073 g of the sample according to the following
equation?
2 K2HPO4 + Ca(OH)2 → Ca(K2PO4)2 + 2 H2O
3.15. What is the percent of Al(OH)3 in a sample when 0.3792 g of the sample is exactly
neutralized by 23.45 mL of 0.1320 M H3PO4 according to the following equation?
3 H3PO4 + Al(OH)3 → Al(H2PO4)3 + 3 H2O
3.16. What is the percent of NaH2PO4 in a sample if 24.18 mL of 0.1032 N NaOH was
used to titrate 0.3902 g of the sample according to the following equation?
NaH2PO4 + 2 NaOH → Na3PO4 + 2 H2O
3.17. A 0.1057 N HCl solution was used to titrate a sample containing Ba(OH)2. If
35.78 mL of HCl was required to exactly react with 0.8772 g of the sample, what is the
percent of Ba(OH)2 in the sample?
2 HCl + Ba(OH)2 → BaCl2 + 2 H2O
3.18. The protein in a 1.2846-g sample of an oat cereal is determined by the Kjeldahl
procedure for organic nitrogen. The sample is digested with H2SO4, the resulting
solution made basic with NaOH, and the NH3 distilled into 50.00 mL of 0.09552 M
HCl. The excess HCl is then back titrated using 37.84 mL of 0.05992 M NaOH. Given
that the protein in grains averages 17.54% m/m N, report the % m/m protein in the
sample of cereal.
3.19. A grain sample was analyzed for nitrogen content by the Kjeldahl method. If
1.2880 g of the grain was used, and 50.00 mL of 0.1009 N HCl was used in the
receiving flask, what is the percent nitrogen in the sample when 5.49 mL of 0.1096 N
NaOH was required for back titration?
3.20. A flour sample was analyzed for nitrogen content by the Kjeldahl method. If
0.9819 g of the flour was used, and 35.10 mL of 0.1009 N HCl was used to titrate the
boric acid solution in the receiving flask, what is the percent nitrogen in the sample?
19
3.21. The concentration of SO2 in atmospheric samples can be determined by bubbling a
sample of air through a trap containing H2O2. Oxidation of SO2 by H2O2 results in the
formation of H2SO4, the amount of which can be determined by titrating with NaOH. In
a typical analysis, a sample of air was passed through the peroxide trap at an average
rate of 1.25 L/min for 60 min and required 10.08 mL of 0.0244 M NaOH to reach the
phenolphthalein end point. Calculate the parts per million of SO2 (mL/L) in the sample
of air. The density of SO2 at the temperature of the air sample is 2.86 mg/mL.
3.22. The concentration of CO2 in air can be determined by an indirect acid–base
titration. A sample of the air is bubbled through a solution containing an excess of
Ba(OH)2, precipitating BaCO3. The excess Ba(OH)2 is back titrated with HCl. In a
typical analysis, a 3.5-L sample of air was bubbled through 50.00 mL of 0.0200 M
Ba(OH)2. Back titrating with 0.0316 M HCl requires 38.58 mL to reach the end point.
Determine the parts per million of CO2 in the sample of air, given that the density of
CO2 at the temperature of the sample is 1.98 g/L.
3.23. The purity of a synthetic preparation of methylethyl ketone (C4H8O) can be
determined by reacting the ketone with hydroxylamine hydrochloride, liberating HCl. In
a typical analysis, a 3.00-mL sample was diluted to 50.00 mL and treated with an excess
of hydroxylamine hydrochloride. The liberated HCl was titrated with 0.9989 M NaOH,
requiring 32.68 mL to reach the end point. Report the percent purity of the sample,
given that the density of methylethyl ketone is 0.805 g/mL.
3.24. Animal fats and vegetable oils are triacylglycerols, or triesters, formed from the
reaction of glycerol (1, 2, 3-propanetriol) with three long-chain fatty acids. One of the
methods used to characterize a fat or an oil is a determination of its saponification
number. When treated with boiling aqueous KOH, an ester is saponified into the parent
alcohol and fatty acids (as carboxylate ions). The saponification number is the number
of milligrams of KOH required to saponify 1.000 g of the fat or oil. In a typical
analysis, a 2.085-g sample of butter is added to 25.00 mL of 0.5131 M KOH. After
saponification is complete, the excess KOH is back titrated with 10.26 mL of 0.5000 M
HCl. What is the saponification number for this sample of butter?
3.25. A 250.0-mg sample of an organic weak acid was dissolved in an appropriate
solvent and titrated with 0.0556 M NaOH, requiring 32.58 mL to reach the end point.
Determine the compound’s equivalent weight.
3.26. What is the molarity of an EDTA solution given the following standardization
data?
a) If 10.0 mg of Mg required 40.08 mL of the EDTA.
b) If 0.0236 g of solid CaCO3 was dissolved and exactly consumed by 12.01 mL
of the EDTA solution.
c) If 30.67 mL of it reacts exactly with 45.33 mg of calcium metal.
d) If 34.29 mL of it is required to react with 0.1879 g of MgCl2.
20
e) If a 100.0-mL aliquot of a zinc solution required 34.62 mL of it (zinc solution
was prepared by dissolving 0.0877 g of zinc in 500.0 mL of solution).
f) If a solution of primary standard CaCO3 was prepared by dissolving 0.5622 g
of CaCO3 in 1000 mL of solution; a 25.00-mL aliquot of it required 21.88 mL of the
EDTA.
g) If 25.00 mL of a solution prepared by complete dissolving 0.4534 g of CaCO3
in 500.0 mL of solution reacts with 34.43 mL of the EDTA solution.
h) If a solution has 0.4970 g of CaCO3 dissolved in 500.0 mL and 25.00 mL of it
reacts exactly with 29.55 mL of the EDTA solution.
i) If 25.00 mL of a CaCO3 solution reacts with 30.13 mL of the EDTA solution
and there is 0.5652 g of CaCO3 per 500.0 mL of the solution
3.27. The amount of calcium in physiologic fluids can be determined by a
complexometric titration with EDTA. In one such analysis, a 0.100-mL sample of blood
serum was made basic by adding 2 drops of NaOH and titrated with 0.00119 M EDTA,
requiring 0.268 mL to reach the end point. Report the concentration of calcium in the
sample as miligrams of calcium per 100 mL.
3.28. After removing the membranes from an eggshell, the shell is dried and its mass
recorded as 5.613 g. The eggshell is transferred to a 250-mL beaker and completely
dissolved in 25 mL of 6 M HCl. After filtering, the solution containing the dissolved
eggshell is diluted to 250 mL in a volumetric flask. A 10.00-mL aliquot is placed in a
125-mL Erlenmeyer flask and buffered to a pH of 10. Titrating with 0.04988 M EDTA
requires 44.11 mL to reach the end point. Determine the amount of calcium in the
eggshell as % m/m CaCO3.
3.29. What is the hardness of the water sample in parts per million CaCO3 in each of the
following situations?
a) If a 100.0-mL aliquot of the water required 27.62 mL of 0.01462 M EDTA for
titration.
b) If 25.00 mL of the water sample required 11.68 mL of 0.01147 M EDTA.
c) If 12.42 mL of a 0.01093 M EDTA solution was needed to titrate 50.00 mL of
the water sample.
d) If, in the experiment for determining water hardness, 75.00 mL of the water
sample required 13.03 mL of a 0.009242 M EDTA solution.
e) If the EDTA solution used for the titrant was 0.01011 M, a 150.0-mL sample
of water was used, and 16.34 mL of the titrant was needed.
f) If 14.20 mL of an EDTA solution, prepared by dissolving 4.1198 g of
Na2H2EDTA⋅2H2O in 500.0 mL of solution, was needed to titrate 100.0 mL of a water
sample.
g) When 100.0 mL of the water required 13.73 mL of an EDTA solution prepared
by dissolving 3.8401 g of Na2H2EDTA⋅2H2O in 500.0 mL of solution.
21
3.30. The concentration of cyanide, CN–, in a copper electroplating bath can be
determined by a complexometric titration with Ag+, forming the soluble Ag(CN)2–
complex. In a typical analysis a 5.00-mL sample from an electroplating bath is
transferred to a 250-mL Erlenmeyer flask, and treated with 100 mL of H2O, 5 mL of
20% m/v NaOH, and 5 mL of 10% m/v KI. The sample is titrated with 0.1012 M
AgNO3, requiring 27.36 mL to reach the end point as signaled by the formation of a
yellow precipitate of AgI. Report the concentration of cyanide as parts per million of
NaCN.
3.31. Before the introduction of EDTA most complexation titrations used Ag+ or CN– as
the titrant. The analysis for Cd2+, for example, was accomplished indirectly by adding
an excess of KCN to form Cd(CN)42–, and back titrating the excess CN– with Ag+,
forming Ag(CN)2–. In one such analysis, a 0.3000-g sample of an ore was dissolved and
treated with 20.00 mL of 0.5000 M KCN. The excess CN– then required 13.98 mL of
0.1518 M AgNO3 to reach the end point. Determine the % m/m Cd in the ore.
3.32. A 0.5131-g sample containing KBr is dissolved in 50 mL of distilled water.
Titrating with 0.04614 M AgNO3 requires 25.13 mL to reach the Mohr end point. A
blank titration requires 0.65 mL to reach the same end point. Report the % m/m KBr in
the sample.
3.33. A 0.1036-g sample containing only BaCl2 and NaCl is dissolved in 50 mL of
distilled water. Titrating with 0.07916 M AgNO3 requires 19.46 mL to reach the Fajans
end point. Report the % m/m BaCl2 in the sample.
3.34. A 0.1093-g sample of impure Na2CO3 was analyzed by the Volhard method. After
adding 50.00 mL of 0.06911 M AgNO3, the sample was back titrated with 0.05781 M
KSCN, requiring 27.36 mL to reach the end point. Report the purity of the Na2CO3
sample.
3.35. If 0.5334 g of K2Cr2O7 was titrated with 24.31 mL of the Na2S2O3 solution, what
is the molarity of the Na2S2O3?
3.36. What is the exact molarity of a solution of K2Cr2O7 if 1.7976 g of Mohr’s salt —
an Fe2+ compound, Fe(NH4)2(SO4)2⋅6H2O — was exactly reacted with 22.22 mL of the
solution? The redox process is:
Fe2+ + Cr2O72– → Fe3+ + 2 Cr3+.
3.37. Consider the standardization of a solution of KIO4 with Mohr’s salt (a compound
of Fe2+, Fe(NH4)2(SO4)2⋅6H2O). What is the exact molarity of the solution if 1.8976 g of
Mohr’s salt was exactly reacted with 24.22 mL of the solution? The oxidation and
reduction are according to the following:
Fe2+ + IO4– → Fe3+ + I–
22
3.38. Consider the standardization of a solution of K2Cr2O7 with iron metal according to
the following:
Fe + Cr2O72– → Fe3+ + 2 Cr3+.
What is the exact molarity of the solution if at the end point 0.1276 g of iron metal was
exactly reacted with 48.56 mL of the solution?
3.39. What is the percent SO3 in a sample if 45.69 mL of a 0.2011 M KIO3 solution is
needed to consume 0.9308 g of sample according to equation:
IO3– + SO3 → IO4– + S2–.
3.40. What is the percent of K2SO4 in a sample if 35.01 mL of a 0.09123 M KBrO3
solution is needed to consume 0.7910 g of sample according to equation:
BrO3– + SO42– → BrO4– + SO32–.
3.41. What is the percent of Fe in a sample titrated with K2Cr2O7, if 2.6426 g of the
sample required 40.12 mL of 0.1096 M K2Cr2O7?
3.42. What is the percent of Sn in a sample of ore if 4.2099 g of the ore was dissolved
and titrated with 36.12 mL of 0.1653 M KMnO4?
3.43. The exact concentration of H2O2 in a solution that is nominally 6% w/v H2O2 can
be determined by a redox titration with MnO4–. A 25-mL aliquot of the sample is
transferred to a 250-mL volumetric flask and diluted to volume with distilled water. A
25 mL aliquot of the diluted sample is added to an Erlenmeyer flask, then diluted with
200 mL of distilled water, and acidified with 20 mL of 25% v/v H2SO4. The resulting
solution is then titrated with a standard solution of KMnO4 until a faint pink color
persists for 30 s. The results are reported as %w/v H2O2.
3.44. The amount of iron in a meteorite was determined by a redox titration using
KMnO4 as the titrant. A 0.4185-g sample was dissolved in acid and the liberated Fe3+
quantitatively reduced to Fe2+, using a reductor column. Titrating with 0.02500 M
KMnO4 requires 41.27 mL to reach the end point. Determine the % m/m Fe2O3 in the
sample of meteorite.
3.45. Under basic conditions, MnO4– can be used as a titrant for the analysis of Mn2+,
with both the analyte and the titrant ending up as MnO2. In the analysis of a mineral
sample for manganese, a 0.5165-g sample is dissolved, and the manganese reduced to
Mn2+. The solution is made basic and then titrated with 0.03358 M KMnO4, requiring
34.88 mL to reach the end point. Calculate the % m/m Mn in the mineral sample.
3.46. The amount of uranium in an ore sample can be determined by an indirect redox
titration. The analysis is accomplished by dissolving the ore in sulfuric acid and
reducing the resulting UO22+ to U4+ with a Walden reductor. The resulting solution is
treated with an excess of Fe3+, forming Fe2+ and U6+. The Fe2+ is titrated with a standard
23
solution of K2Cr2O7 to a visual end point. In a typical analysis, a 0.315-g sample of ore
is passed through the Walden reductor and treated with an excess of Fe3+. Titrating with
0.00987 M K2Cr2O7 requires 10.52 mL. What is the % m/m U in the sample?
3.47. The concentration of carbon monoxide CO in air can be determined by passing a
known volume of air through a tube containing I2O5, resulting in the formation of CO2
and I2. The I2 is removed from the tube by distillation and is collected in a solution
containing an excess of KI, producing I3–. The I3– is titrated with a standard solution of
Na2S2O3. In a typical analysis, a 4.79-L sample of air was sampled as described here,
requiring 7.17 mL of 0.00329 M Na2S2O3 to reach the end point. If the air has a density
of 1.23⋅10–3 g/mL, determine the concentration of carbon monoxide in the air, in parts
per million.
3.48. The level of dissolved oxygen in a water sample can be determined by the Winkler
method. In a typical analysis, a 100.0-mL sample is made basic, and treated with a
solution of MnSO4, resulting in the formation of MnO2. An excess of KI is added, and
the solution is acidified, resulting in the formation of Mn2+ and I2. The liberated I2 is
titrated with a solution of 0.00870 M Na2S2O3, requiring 8.90 mL to reach the starch
indicator end point. Calculate the concentration of dissolved oxygen as parts per million
of O2.
3.49. Find a real-world titrimetric analysis in a methods book, or journal or on a website
and report on the details of the procedure according to the following scheme:
a) Title.
b) General information, including type of material examined, the name of the
analyte, sampling procedures, and sample preparation procedures.
c) Specifics, including what titrant is used and how it is standardized (including
what primary standards are used); what solutions are needed and how they are prepared;
what glassware is needed and for what; what end point detection method is used for
both standardization and analysis steps; what reactions (write balanced equations) are
involved in both the standardization and analysis steps; whether it is a direct, indirect, or
back titration (both standardization and analysis steps); and any special procedures,
potential problems, etc.
d) Data handling and reporting.
e) References.
24
4. INSTRUMENTAL ANALYSIS
4.1. Provide the missing information in the following table:
Wavelength (m)
4.50⋅10–9
Frequency (s–1)
Wavenumber (cm–1) Energy (J/molecule)
1.33⋅1015
3215
7.20⋅10–19
4.2. Provide the missing information in the following table:
[Analyte]
(M)
1.40⋅10–4
–4
2.56⋅10
1.55⋅10–3
–3
4.35⋅10
1.20⋅10–4
Absorbance
Transmittance
(%)
0.563
0.225
0.167
33.3
21.2
81.3
Molar absorptivity (M–1cm–1)
1120
750
440
565
1550
Pathlength
(cm)
1.00
1.00
5.00
1.00
10.00
4.3. What is the molar absorptivity given that the absorbance is 0.619, the pathlength is
1.0 cm, and the concentration is 4.23⋅10–6 M?
4.4. Calculate the concentration of an analyte in a solution given that the measured
absorbance is 0.592, the absorptivity is 3.22⋅104 L⋅mol–1⋅cm–1, the pathlength is 1.00 cm.
4.5. What is the concentration of an analyte given that the percent transmittance is
70.3%, the pathlength is 1.0 cm, and the molar absorptivity is 8382 L⋅mol–1⋅cm–1?
4.6. What is the pathlength in centimeters when the molar absorptivity for a given
absorbing species is 1.32⋅103 L⋅mol–1⋅cm–1, the concentration is 0.000923 M, and the
absorbance is 0.493?
4.7. What is the transmittance when the molar absorptivity for a given absorbing species
is 2.81⋅102 L⋅mol–1⋅cm–1, the pathlength is 1.00 cm, while the concentration of the
analyte is 0.000187 M?
4.8. What is the molar absorptivity when the percent transmittance is 56.2%, the
pathlength is 2.00 cm, and the concentration of the light-absorbing analyte equals
0.0000748 M?
25
4.9. A phenol standard with a concentration of 4.00 ppm has an absorbance of 0.424 at a
wavelength of 460 nm using a 1.00-cm cell. A water sample is steam-distilled, and a
50.00-mL aliquot of the distillate is placed in a 100-mL volumetric flask and diluted to
volume with distilled water. The absorbance of this solution is found to be 0.394. What
is the concentration of phenol (in parts per million) in the water sample?
4.10. The concentration of SO2 in a sample of air was determined by the p-rosaniline
method. The SO2 was collected in a 10.00-mL solution, by pulling the air through the
solution for 75 min at a rate of 1.6 L/min. After adding p-rosaniline and formaldehyde,
the colored solution was diluted to 25 mL in a volumetric flask. The absorbance was
measured at 569 nm in a 1-cm cell, yielding a value of 0.485. A standard sample was
prepared by substituting a 1.00-mL sample of a standard solution containing the
equivalent of 15.00 ppm SO2 for the air sample. The absorbance of the standard was
found to be 0.181. Report the concentration of SO2 in the air in parts per million. The
density of air may be taken as 1.18 g/L.
4.11. In the colorimetric method for the free chlorine residual, which is reported as parts
per million of Cl2, the oxidizing power of free chlorine converts the colorless amine
N,N-diethyl-p-phenylenediamine to a colored dye that absorbs strongly over the
wavelength range of 440–580 nm. Analysis of a set of calibration standards gave the
following results:
ppm Cl2
0
0.50
1.00
1.50
2.00
absorbance
0.000
0.270
0.543
0.813
1.084
A sample from a public water supply is analyzed to determine the free chlorine residual,
giving an absorbance of 0.113. What is the free chlorine residual for the sample in parts
per million Cl2?
4.12. A series of five standard copper solutions are prepared, and the absorbances are
measured as indicated below. Plot the data and determine the concentration of the
unknown.
C(ppm)
1
2
3
4
5 Unknown
A
0.104
0.198
0.310
0.402
0.500
0.334
4.13. EDTA forms colored complexes with a variety of metal ions that may serve as the
basis for a quantitative spectrophotometric method of analysis. The molar absorptivities
of the EDTA complexes of Cu2+, Co2+, and Ni2+ at three wavelengths are summarized in
the following table (all values of ε are in mol–1⋅cm–1):
Metal
ε462.9
ε732.0
ε378.7
Co2+
Cu2+
Ni2+
15.8
2.32
1.79
2.11
95.2
3.03
3.11
7.73
13.5
26
The pathlength for all measurements is 1.00 cm. Using this information, determine:
a) the concentration of Cu2+ in a solution that has an absorbance of 0.338 at a
wavelength of 732.0 nm;
b) the concentrations of Cu2+ and Co2+ in a solution that has an absorbance of
0.453 at a wavelength of 732.0 nm and 0.107 at a wavelength of 462.9 nm;
c) the concentrations of Cu2+, Co2+, and Ni2+ in a sample that has an absorbance of
0.423 at a wavelength of 732.0 nm, 0.184 at a wavelength of 462.9 nm, and 0.291 at a
wavelength of 378.7 nm.
4.14. The following data were obtained using a nitrate electrode for a series of standard
solutions of nitrate:
[NO3–], M
10–1
10–2
10–3
10–4
E, mV
85
150
209
262
Plot the calibration curve for this analysis. What is the nitrate ion concentration in a
solution for which E = 184 mV?
4.15. The following data have been collected for a series of penicillin standards, using a
membrane electrode in which the enzyme penicillinase is immobilized in a gel that is
coated on a glass pH electrode:
[Penicillin], M
1.0⋅10–6
1.0⋅10–5
1.0⋅10–4
2.0⋅10–4
Potential, mV
80
96
135
153
[Penicillin], M
1.0⋅10–3
2.0⋅10–3
1.0⋅10–2
Potential, mV
190
204
220
Construct a calibration curve for the electrode, and report:
a) the range of concentrations in which a linear response is observed,
b) the concentration of penicillin in a sample that yields a potential of 142 mV.
4.16. For the analysis of tap water, to three 25.0-mL samples five additions of a
standard solution of 100.0-ppm F– were added, measuring the potential.
Additions of
standard F–, mL
0.00
1.00
2.00
3.00
4.00
5.00
Potential, mV
Trial 2
–82
–119
–133
–142
–148
–153
Trial 1
–79
–119
–133
–142
–149
–154
Trial 3
–81
–118
–133
–142
–148
–153
Determine the parts per million of F– in the tap water, with the confidence interval.
27
4.17. For the analysis of toothpaste a 0.3619-g sample was transferred to a 100-mL
volumetric flask and diluted to volume with distilled water. Three 20.0-mL aliquots
were removed, and the potential was measured with an F– ion-selective electrode. Five
separate 1.00-mL additions of a 100.0-ppm solution of F– were added to each,
measuring the potential following each addition.
Additions of
standard F–, mL
0.00
1.00
2.00
3.00
4.00
5.00
Potential, mV
Trial 2
–54
–82
–94
–103
–108
–112
Trial 1
–55
–82
–94
–102
–108
–112
Trial 3
–55
–83
–94
–102
–109
–113.
Report the parts per million of F– in the sample of toothpaste, calculating the confidence
interval at 95%.
4.18. The concentration of NO3– in a water sample is determined by a one-point
standard addition using an NO3– ion-selective electrode. A 25.00-mL sample is placed
in a beaker, and a potential of +0.102 V is measured. A 1.00-mL aliquot of a 200.0 ppm
standard solution of NO3– is added, after which the potential is found to be +0.089 V.
Report the concentration of NO3– in parts per million.
4.19. The purity of a sample of picric acid, C6H3N3O7, is determined by controlledpotential coulometry, converting picric acid to triaminophenol, C6H9N3O. A 0.2917-g
sample of picric acid is placed in a 1000-mL volumetric flask and diluted to volume. A
10.00-mL portion of this solution is transferred to a coulometric cell and diluted till the
Pt cathode is immersed. The exhaustive electrolysis of the sample requires 21.67 C of
charge. Report the purity of the picric acid.
4.20. The concentration of H2S in the drainage from an abandoned mine can be
determined by a coulometric titration using KI as a mediator and I3– as the “titrant.”
H2S(aq) + I3–(aq) + 2 H2O(l) → 2 H3O+(aq) + 3 I–(aq) + S(s)
A 50.00-mL sample of water is placed in a coulometric cell, along with an excess of KI
and a small amount of starch as an indicator. Electrolysis is carried out at a constant
current of 84.6 mA, requiring 386 s to reach the starch end point. Report the
concentration of H2S in the sample in parts per million.
4.21. The amount of sulfur in aromatic monomers can be determined by differential
pulse polarography. Standard solutions are prepared for analysis, dissolving 1.000 mL
of the purified monomer in 25.00 mL of an electrolytic solvent, adding a known amount
28
of S, de-aerating, and measuring the peak current. The following results were obtained
for a set of calibration standards:
Added S, μg
0
28
56
112
168
Peak current, μA
0.14
0.70
1.23
2.41
3.42
Analysis of a 1.000-mL sample, treated in the same manner as the standards, gives a
peak current of 1.77 μA. Report the amount of sulfur present in the sample in
milligrams per milliliter.
4.22. The purity of a sample of K3Fe(CN)6 was determined using linear-potential scan
hydrodynamic voltammetry at a glassy carbon electrode using the method of external
standards. The following data were obtained for a set of calibration standards.
[K3Fe(CN)6], mM
2.0
4.0
6.0
8.0
10.0
Limiting current, μA
127
252
376
500
624
A sample was prepared for analysis, diluting a 0.246-g sample to volume in a 100-mL
volumetric flask. The limiting current for the sample was found to be 444 μA. Report
the purity of this sample of K3Fe(CN)6.
4.23. A certain sample is a mixture of four organic liquids and these liquids exhibit the
following retention times in a gas chromatography experiment. Some known liquids
were also injected into the chromatograph and the following data were determined:
Liquid
A
B
C
D
Retention Time
1.6 min
2.2 min
4.7 min
9.8 min
Liquid
Benzene
Toluene
Ethylbenzene
n-Propylbenzene
Isopropylbenzene
Retention Time
0.5 min
1.6 min
3.4 min
4.7 min
5.8 min
a) Can you tell which liquids from these five are definitely not present? If not,
why not? If so, which liquids are they?
b) What liquids are possibly present?
4.24. An injection of 3.0 mL of methylene chloride (density = 1.327 g/mL) gave a peak
size of 3.74 cm2. The injection of 3.0 mL of an unknown sample (density = 1.174 g/mL)
gave a methylene chloride peak size of 1.02 cm2. Calculate a response factor for
methylene chloride and the percent of methylene chloride in the sample.
4.25. Consider the gas chromatographic analysis of plant material for a pesticide
residue. Two grams of the material is chopped up and placed in a Soxhlet extractor and
the pesticide quantitatively extracted into an appropriate solvent. Following this, the
solvent is evaporated to near dryness and the residue is diluted to volume in a 25-mL
flask. Then 2.5 mL of this solution and standards is injected in a gas chromatograph
with the following results:
29
Concentration (ppm)
5.0
10.0
15.0
Peak Area
1168
2170
3214
Concentration (ppm)
20.0
25.0
Sample
Peak Area
4079
5392
3577
What is the parts per million of pesticide in the original plant material?
4.26. Find a real-world visible spectrophotometric analysis in a methods book or a
journal, and report on the details of the procedure according to the following scheme:
a) Title.
b) General information, including the type of material examined, the name of the
analyte, sampling procedures, and sample preparation procedures.
c) Specifics, including whether a Beer’s law plot is used, what color-developing
reagent is used (if there is one), reactions involved to obtain the color, what wavelength
is used, how the data are gathered, concentration levels for standards, how the standards
are prepared, and potential problems.
d) Data handling and reporting.
e) References.
4.27. Find a real-world electroanalytical analysis in a methods book or journal and
report on the details of the procedure according to the following scheme:
a) Title.
b) General information, including type of material examined, the name of the
analyte, sampling procedures, and sample preparation procedures.
c) Specifics, including the specific experiment (titration, series of standard
solutions, Karl Fischer, voltammetric, amperometric), what the titrant is and how it is
standardized or how the calibration curve is created, quantitation procedure, how the
data are gathered, concentration levels for standards, how standards are prepared, and
potential problems.
d) Data handling and reporting.
e) References.
4.28. Find a real-world gas chromatographic analysis in a methods book or journal, and
report on the details of the procedure according to the following scheme.
a) Title.
b) General information, including type of material examined, name of the analyte,
sampling procedures, and sample preparation procedures.
c) Specifics, including whether an internal standard is used, what stationary phase
and solid support are used, temperature program, mobile phase used and its flow rate,
what detector is used, how the data are gathered, concentration levels for standards, how
standards are prepared, and potential problems.
d) Data handling and reporting.
e) References.
30
REFERENCES
1. Dingrando, Laurel. Glencoe Chemistry: Matter and Change / Laurel
Dingrando, Kathleen V. Gregg, Nicolas Hainen, Cheryl Wistrom. – Glencoe / McGrawHill, 2004. – 1021 p.
2. Harvey, David. Modern Analytical Chemistry / David Harvey. – International
Edition: McGraw-Hill Higher Education, 2000. – 816 p.
3. Kealey, D. Analytical Chemistry / D. Kealey, P.J. Haines. – Oxford: BIOS
Scientific Publishers Limited, 2006. – 353 p.
4. Kenkel, John. Analytical Chemistry for Technicians / John Kenkel. – CRC
Press Limited, 2003. – 547 p.
5. Kotz, John C. Chemistry and Chemical Reactivity / John C. Kotz, Paul M.
Treichel, John R. Townsend. – Thomson Brooks / Cole, 2009. – 1256 p.
31
PERIODIC TABLE
I
II
III
IV
V
H
1
2
3
4
5
6
7
Hydrogen
1
1.0079
Li
Lithium
3
6.94
Na
Sodium
11
22.99
K
Potassium
19
39.098
Cu
Copper
29
63.54
Rb
Rubidium
37
85.47
Ag
Silver
47
107.87
Cs
Cesium
55
132.905
Au
Gold
79
196.97
Fr
Francium
87
[223]
Lanthanides
Gd
64
Gadolinium
157.2
Actinides
Cm
96
Curium
[247]
Be
B
Beryllium
4
9.012
Mg
Magnesium
12
24.305
Ca
Calcium
20
40.08
Zn
Zinc
30
65.38
Sr
Strontium
38
87.62
Cd
Cadmium
48
112.41
Ba
Barium
56
137.33
Hg
Mercury
80
200.5
Ra
Radium
88
226.03
La
57
Tb
65
Ac
89
Bk
97
C
N
Boron
5
10.81
Al
Aluminum
13
26.98
Sc
Scandium
21
44.956
Ga
Gallium
31
69.72
Y
Yttrium
39
88.91
In
Indium
49
114.82
Carbon
Nitrogen
6
12.011 7
14.0067
Si
P
Silicon
Phosphorus
14
28.085 15
30.974
V
Ti
Vanadium
Titanium
50.94
22
47.90 23
Ge
As
Germanium
Arsenic
32
72.59 33
74.92
Zr
Nb
Zirconium
Niobium
40
91.22 41
92.906
Sn
Sb
Tin
Antimony
50
118.69 51
121.75
Ta
Hf
Tantalum
Hafnium
La–Lu
180.95
72
178.49 73
Tl
Pb
Bi
Thallium
Lead
Bismuth
81
204.3 82
207.2 83
208.98
Rf
Db
Rutherfordium
Dubnium
Ac–(Lr)
104
[261] 105
[262]
Lanthanum
138.905
Terbium
158.93
Actinium
[227]
Berkelium
[247]
Ce
58
Dy
66
Th
90
Cf
98
32
Cerium
140.12
Dysprosium
162.50
Thorium
232.038
Californium
[251]
Pr Praseodymium
59
140.9077
Ho
Holmium
67
164.93
Pa
Protactinium
91
231.036
Es
Einsteinium
99
[254]
Appendix 1
OF CHEMICAL ELEMENTS
VI
VII
VIII
(H)
O
F
Oxygen
Fluorine
8
15.999 9
18.998
S
Cl
Sulfur
Chlorine
16
32.06 17
35.453
Mn
Cr
Manganese
Chromium
54.938
24
51.996 25
Se
Br
Selenium
Bromine
34
78.96 35
79.904
Mo
Tc
Molybdenum
Technetium
42
95.94 43
98.906
Te
I
Tellurium
Iodine
52
127.6 53
126.90
Re
W
Rhenium
Tungsten
186.21
74
183.8 75
Po
At
Polonium
Astatine
84
[209] 85
[210]
Sg
Bh
Seaborgium
Bohrium
106
[266] 107
[264]
Nd
60
Er
68
U
92
Fm
100
He
Fe
26
Iron
55.847
Ru
Ruthenium
44
101.07
Os
Osmium
76
190.2
Hs
Hassium
108
[277]
Neodymium Pm
Promethium
144.24 61
[145]
Erbium Tm
Thulium
167.26 69
168.93
Uranium Np
Neptunium
238.029 93
237.048
Fermium Md Mendelevium
[257] 101
[258]
33
Sm
62
Yb
70
Pu
94
No
102
Helium
2
4.0026
Ne
Neon
10
20.179
Ar
Argon
18
39.948
Ni
Co
Nickel
Cobalt
58.70
27
58.933 28
Kr
Krypton
36
83.80
Rh
Pd
Rhodium
Palladium
45
102.9 46
106.4
Xe
Xenon
54
131.3
Pt
Ir
Platinum
Iridium
195.1
77
199.2 78
Rn
Radon
86
[222]
Mt
Meitnerium
109
[268]
Samarium
150.4
Ytterbium
173.04
Plutonium
[244]
Nobelium
[255]
Eu
63
Lu
71
Am
95
Lr
103
Europium
151.96
Lutetium
174.967
Americium
[243]
Lawrencium
[256]
Appendix 2
Elements and Electronegative Components
Symbol
Ac
Al
Ag
Am
Ar
As
At
Au
B
Ba
Be
Bh
Bi
Bk
Br
C
Ca
Cd
Ce
Cf
Cl
Cm
Co
Cr
Cs
Cu
Db
Dy
Er
Es
Eu
F
Fe
Fm
Fr
Name
Transcription
actinium
aluminum
silver
americium
argon
arsenic
astatine
gold
boron
barium
beryllium
bohrium
bismuth
berkelium
bromine
carbon
calcium
cadmium
cerium
californium
chlorine
curium
cobalt
chromium
cesium
copper
dubnium
dysprosium
erbium
einsteinium
europium
fluorine
iron
fermium
francium
αk_'tin_i: _əm
ə_'lu:m_ə_nəm
'sil_vər
αm_ə_'ris_i: _əm
'a:r_gən
'a:rs_ən_ik
'αs_tə_ti:n
gould
'bo:_rən
'bαr_i:_əm
bə_'ril_i: _əm
'bo:r_i: _əm
'biz_məθ
'bə:r_kli: _əm
'brou_mi:n
'ka:r_bən
'kαl_si:_əm
'kαd_mi:_əm
'sir_i:_əm
kalə_'fo:r_ni:_əm
'klo:r_i:n
'kju:r_i:_əm
'kou_bo:lt
'krou_mi:_əm
'si:_zi:_əm
'kop_ər
'du:b_ni:_əm
dis_'prou_zi:_əm
'ə:r_bi:_əm
aın_'staın_i:_əm
yu:_'rou_pi:_əm
'flu:r_i:n
'aı_ərn
'fer_mi:_əm
'frαn_si:_əm
34
Electronegative
component
Transcription
arsenide
'a:rs_ən_aıd
boride
'bo:r_aıd
beryllide
bə_'ril_aid
bromide
carbide
'brou_maıd
'ka:r_baıd
chloride
'klo:r_aıd
fluoride
'flu:r_aıd
Appendix 2 (continued)
Symbol
Ga
Gd
Ge
H
He
Hf
Hg
Ho
Hs
I
In
Ir
K
Kr
La
Li
Lr
Lu
Md
Mg
Mn
Mo
Mt
N
Na
Nb
Nd
Ne
Ni
No
Np
O
Os
P
Pa
Pb
Pd
Name
gallium
gadolinium
germanium
hydrogen
helium
hafnium
mercury
holmium
hassium
iodine
indium
iridium
potassium
krypton
lanthanum
lithium
lawrencium
lutetium
mendelevium
magnesium
manganese
molybdenum
meitnerium
nitrogen
sodium
niobium
neodymium
neon
nickel
nobelium
neptunium
oxygen
osmium
phosphorus
protactinium
lead
palladium
Transcription
'gαl_i:_əm
gαd_əl_'in_i:_əm
jə:r_'meın_i:_əm
'haı_drə_jən
'hi:_li:_əm
'hαf_ni:_əm
'mə:r_kyə_ri:
'houl_mi:_əm
'ha:_si:_əm
'aı_ə_daın
'in_di:_əm
i_'rid_i:_əm
pə_'tαs_i:_əm
'krip_tən
'lαn_θə_nəm
'liθ_i:_əm
'lou_'ren_si:_əm
lu:_ti: _shəm
'men_də_li:_vi:_əm
mαg_'ni:_zi:_əm
'mαŋ_gə_ni:s
mə_'lib_de_nəm
maıt_'nir_i:_əm
'naı_trə_jən
'soud_i:_əm
naı_'ou_bi:_əm
ni:_ou_'dim_i:_əm
'ni:_on
'nik_əl
nou_'bel_i:_əm
nep_'tu:_ni:_əm
'ok_sə_jən
'oz_mi:_əm
'fos_fə_rəs
prout_αk_'tin_i:_əm
led
pə_'leıd_i:_əm
35
Electronegative
component
Transcription
germanide
hydride
'jə:r_mə_naıd
'haı_draıd
iodide
'aı_ə_daıd
nitride
'naı_traıd
oxide
'ok_saıd
phosphide
'fo_sfaıd
plumbide
'pləm_baıd
Appendix 2 (end)
Symbol
Name
Transcription
Po
Pm
Pr
Pt
Pu
Ra
Rb
Re
Rf
Rh
Rn
Ru
S
Sb
Sc
Se
Sg
Si
Sm
Sn
Sr
Ta
Tb
Tc
Te
Th
Ti
Tl
Tm
U
V
W
Xe
Y
Yb
Zn
Zr
polonium
promethium
praseodymium
platinum
plutonium
radium
rubidium
rhenium
rutherfordium
rhodium
radon
ruthenium
sulfur
antimony
scandium
selenium
seaborgium
silicon
samarium
tin
strontium
tantalum
terbium
technetium
tellurium
thorium
titanium
thallium
thulium
uranium
vanadium
tungsten
xenon
yttrium
ytterbium
zinc
zirconium
pə_'lou_ni:_əm
prə_'mi:_thi:_əm
preı_zi:_ou_'dim_i:_əm
'plαt_ən_əm
plu:_'tou_ni:_əm
'reı_d_i:_əm
ru:_ 'bid_i:_əm
'ri:_ni:_əm
rəð_ər_'fo:r_di:_əm
'roud_i:_əm
'reı_dən
ru:_ 'thi:_ni:_əm
'səl_fər
'αn_tə_'mou_ni:
'skαn_di:_əm
sə_'li:_ni:_əm
si:_ 'bo:rg_i:_əm
'sil_ə_kən
sə_'mαr_i:_əm
tin
'stron_ti:_əm
'tαnt_əl_əm
'tə:r_bi:_əm
tek_'ni:_shi:_əm
tə_'lu_ri:_əm
'tho:r_i:_əm
taı_'teı_ni:_əm
'θαl_i:_əm
'θu:_li:_əm
yə_'reı_ni:_əm
və_'neıd_i:_əm
'təŋ_stən
'zi:_non
'i_tri:_əm
i_'tə:r_bi:_əm
ziŋk
zə:r_'kou_ni:_əm
36
Electronegative
component
Transcription
sulfide
'səl_faıd
selenide
'sel_ə_naıd
silicide
'sil_ə_saıd
telluride
tə_'lu_raıd
Appendix 3
Acids and Anions
Formula
Acid
HCl
HClO
HClO2
HClO3
HClO4
hydrochloric
hypochlorous
chlorous
chloric
perchloric
Transcription
haı_drə_'klo:r_ik
haı_pə_'klo:r_əs
'klo:r_əs
'klo:r_ik
pə:r_'klo:r_ik
Anion
chloride
hypochlorite
chlorite
chlorate
perchlorate
Transcription
'klo:r_aıd
haı_pə_'klo:r_aıt
'klo:r_aıt
'klo:r_eıt
pə:r_'klo:r_eıt
(similar with other halogens)
HCN
HMnO4
HNO2
HNO3
HOCN
HSCN
CH3COOH
H2C2O4
H2CO3
H2Cr2O7
H2CrO4
H2S
H2SiO3
H2S2O3
H2SO3
H2SO4
H3AsO3
H3AsO4
H3BO3
H3PO3
H3PO4
hydrocyanic
permanganic
nitrous
nitric
cyanic
thiocyanic
acetic
oxalic
carbonic
dichromic
chromic
hydrosulfuric
silicic
thiosulfuric
sulfurous
sulfuric
arsenious
arsenic
boric
phosphorous
phosphoric
haı_drou_saı_'an_ik
pə:r_mαn_'gαn_ik
'naı_trəs
'naı_trik
saı_'αn_ik
θaı_ou_saı_'αn_ik
ə_'si:t_ik
ok_'sαl_ik
ka:r_'bon_ik
daı_'krou_mik
'krou_mik
haı_drə_səl_'fyur_ik
sə_'lis_ik
θaı_ə_səl_'fyur_ik
'səl_fə_rəs
'səl'fyur_ik
a:r_'si:n_i:_əs
a:r_'sen_ik
'bo:r_ik
'fos_fə_rəs
fos_'fo:r_ik
37
cyanide
permanganate
nitrite
nitrate
cyanate
thiocyanate
acetate
oxalate
carbonate
dichromate
chromate
sulfide
silicate
thiosulfate
sulfite
sulfate
arsenite
arsenate
borate
phosphite
phosphate
'saı_ə_naıd
pə:r_'mαŋ_gə_neıt
'naı_traıt
'naı_treıt
'saı_ə_neıt
θaı_ou_'saı_ə_neıt
'αs_ə_teıt
'ok_sə_leıt
'ka:r_bə_nət
daı_'krou_meıt
'krou_meıt
'səl_faıd
'sil_ə_kət
θaı_ə_'səl_feıt
'səl_faıt
'səl_feıt
'a:r_sə_naıt
'a:rs_ən_eıt
'bo: _reıt
'fos_faıt
'fos_'feıt
Appendix 4
Critical Values for t-Test for Chosen Confidence Intervals
(Two-Tailed Test)
Number of
experiments
2
3
4
5
6
7
8
9
10
11
12
13
14
15
∞
Degrees of
freedom
1
2
3
4
5
6
7
8
9
10
11
12
13
14
∞
90%
6.31
2.92
2.35
2.13
2.02
1.94
1.89
1.86
1.83
1.81
1.80
1.78
1.77
1.76
1.64
Confidence intervals
95%
12.7
4.30
3.18
2.78
2.57
2.45
2.36
2.31
2.26
2.23
2.20
2.18
2.16
2.14
1.96
99%
63.7
9.92
5.84
4.60
4.03
3.71
3.50
3.36
3.25
3.17
3.11
3.06
3.01
2.98
2.58
Appendix 5
Critical Values for Q-Test
N/α
3
4
5
6
7
8
9
10
0.1
0.941
0.765
0.642
0.560
0.507
0.468
0.437
0.412
0.05
0.970
0.829
0.710
0.625
0.568
0.526
0.493
0.466
0.04
0.976
0.846
0.729
0.644
0.586
0.543
0.510
0.483
38
0.02
0.988
0.889
0.780
0.698
0.637
0.590
0.555
0.527
0.01
0.994
0.926
0.821
0.740
0.680
0.634
0.598
0.568
Appendix 6
F-Table for Two-Tailed Test (95% Confidence Level)
f2/f1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
∞
1
647.8
38.51
17.44
12.22
10.01
8.813
8.073
7.571
7.209
6.937
6.724
6.544
6.414
6.298
6.200
6.115
6.042
5.978
5.922
5.871
5.024
2
799.5
39.00
16.04
10.65
8.434
7.260
6.542
6.059
5.715
5.456
5.256
5.096
4.965
4.857
4.765
4.687
4.619
4.560
4.508
4.461
3.689
3
864.2
39.17
15.44
9.979
7.764
6.599
5.890
5.416
5.078
4.826
4.630
4.474
4.347
4.242
4.153
4.077
4.011
3.954
3.903
3.859
3.116
4
899.6
39.25
15.10
9.605
7.388
6.227
5.523
5.053
4.718
4.468
4.275
4.121
3.996
3.892
3.804
3.729
3.665
3.608
3.559
3.515
2.786
5
921.8
39.30
14.88
9.364
7.146
5.988
5.285
4.817
4.484
4.236
4.044
3.891
3.767
3.663
3.576
3.502
3.438
3.382
3.333
3.289
2.567
6
937.1
39.33
14.73
9.197
6.978
5.820
5.119
4.652
4.320
4.072
3.881
3.728
3.604
3.501
3.415
3.341
3.277
3.221
3.172
3.128
2.408
7
948.2
39.36
14.62
9.074
6.853
5.695
4.995
4.529
4.197
3.950
3.759
3.607
3.483
3.380
3.293
3.219
3.156
3.100
3.051
3.007
2.288
8
956.7
39.37
14.54
8.980
6.757
5.600
4.899
4.433
4.102
3.855
3.664
3.512
3.388
3.285
3.199
3.125
3.061
3.005
2.956
2.913
2.192
9
963.3
39.39
14.47
8.905
6.681
5.523
4.823
4.357
4.026
3.779
3.588
3.436
3.312
3.209
3.123
3.049
2.985
2.929
2.880
2.837
2.114
10
968.6
39.40
14.42
8.844
6.619
5.461
4.761
4.295
3.964
3.717
3.526
3.374
3.250
3.147
3.060
2.986
2.922
2.866
2.817
2.774
2.048
15
984.9
39.43
14.25
8.657
6.428
5.269
4.568
4.101
3.769
3.522
3.330
3.177
3.053
2.949
2.862
2.788
2.723
2.667
2.617
2.573
1.833
20
993.1
39.45
14.17
8.560
6.329
5.168
4.467
3.999
3.667
3.417
3.226
3.073
2.948
2.844
2.756
2.681
2.616
2.559
2.509
2.464
1.708
∞
1018
39.50
13.90
8.257
6.015
4.849
4.142
3.670
3.333
3.080
2.883
2.725
2.596
2.487
2.395
2.316
2.247
2.187
2.133
2.085
1.000
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ
Модуль 3
АНАЛИТИЧЕСКАЯ ХИМИЯ
Учебное пособие
39