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Министерство образования и науки Российской Федерации
Федеральное агентство по образованию
Южно-Уральский государственный университет
Кафедра аналитической химии
Ш143.21-9
Д182
Е.И. Данилина
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ
Модуль 1
БАЗОВЫЕ ХИМИЧЕСКИЕ ПОНЯТИЯ
Учебное пособие
Челябинск
Издательство ЮУрГУ
2009
УДК 54(075.8)
ББК Ш143.21-923
Д182
Одобрено
учебно-методической комиссией химического факультета
Рецензенты:
Балыкин В.П., Бояльская Т.А.
Д182
Данилина, Е.И.
Химия на английском языке. Модуль 1. Базовые химические
понятия: учебное пособие. – Челябинск: Изд-во ЮУрГУ, 2008. – 37 с.
Учебное пособие составлено на английском языке по материалам
американских и английских учебников по химии для колледжей и
университетов и предназначено для практических занятий и
самостоятельной работы студентов. В учебном пособии предложены
вопросы и задачи, охватывающие круг базовых химических понятий и
соответствующие школьному курсу химии. В приложениях приведены
необходимые справочные материалы для численного решения задач и
их устного чтения: Периодическая таблица, транскрипция названий
элементов и соединений по правилам ИЮПАК.
Пособие предназначено для студентов 1 курса химического
факультета.
УДК 54(075.8)
ББК Ш143.21-923
© Издательство ЮУрГУ, 2009
2
CONTENTS
1. Formulas and Names of Elements and Compounds..........................................4
2. Atomic and Molecular Mass. Mole Concept......................................................9
3. Calculating the Percentage by Mass.................................................................14
4. Concentration of Solutions...............................................................................18
5. Balancing Chemical Equations.........................................................................21
6. Calculations Based on Chemical Equations......................................................25
References.............................................................................................................30
Appendix 1. Periodic Table of Chemical Elements..............................................31
Appendix 2. Elements and Electronegative Components.....................................33
Appendix 3. Acids and Anions..............................................................................36
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1. FORMULAS AND NAMES
OF ELEMENTS AND COMPOUNDS
1.1. What is the chemical symbol for each of the following elements?
a) iron;
b) silver;
c) phosphorus;
d) calcium:
e) mercury;
f) nickel.
1.2. What are the symbols for the following elements?
a) magnesium;
b) manganese:
c) cobalt:
d) argon:
e) silicon;
f) beryllium.
1.3. What is the name of each of the following element?
a) K;
b) Al;
c) C;
d) N;
e) Ne;
f) Na;
g) O;
h) Os;
i) He.
1.4. Give the names of the elements for which the symbols are…
a) H;
b) Rb;
c) Ba;
d) Sr;
e) S;
f) Xe;
g) F;
h) Cl;
i) Bi.
1.5. What are the empirical formulas of each of the following?
a) N2O4;
b) C6H12O6;
c) C8H8;
d) CH3COOH.
1.6. The structural formula for glucose is
H
H
OH
O
HO C
H
H
H C OH
H
H C
OH
OH
H
O
H C OH
CH2OH
H
C
H
CH2OH
OH
What are the molecular and empirical formulas of glucose?
1.7. Choose the elements that form monoatomic anions from the following list;
name the elements and the anions:
Zn, H, Al, S, K, Hg, F, Ag, I, Sb, Cu, V, P, Cl, Na, Si, He, Cs, Br, Cr, N, Fe, Pb, Cd,
C, W, Ne, Zr.
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1.8. How are the cations named in compounds? (Pay attention to Roman numerals.)
+1
Li+
Na+
K+
Ag+
Cu+
Hg+
NH4+
+2
Mg2+
Ca2+
Ba2+
Zn2+
Ni2+
Fe2+
Cu2+
Hg2+
Pb2+
Sn2+
Co2+
+3
Al3+
Bi3+
Cr3+
Fe3+
Co3+
+4
Pb4+
Sn4+
1.9. What are the symbols of the following monoatomic anions?
–1
bromide
chloride
fluoride
hydride
iodide
–2
–3
oxide
peroxide
sulfide
nitride
phosphide
1.10. Name the following compounds:
a) MgCl2; b) AlBr3; c) Li3N;
d) CaO;
e) CaS;
f) Al2O3.
1.11. Name the following compounds:
a) CrCl3; b) CuO;
c) Mn2O3;
d) SnO2;
e) Hg2Cl2; f) PbS;
g) FeCl3; h) PbI2;
i) Pb3O4.
1.12. Write the formulas of the following compounds:
a) calcium chloride;
b) zinc sulfide;
c) strontium fluoride;
d) magnesium oxide;
e) silver bromide;
f) barium chloride;
g) mercury(I) iodide;
h) tin(IV) chloride.
1.13. Write the chemical formulas for the following compounds:
a) sodium oxide;
b) barium sulfide;
c) magnesium nitride; d) silver iodide;
e) calcium carbide;
f) iron(III) chloride.
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1.14. Write the formulas of the following compounds:
a) magnesium bromide; b) aluminum carbide;
c) copper(I) chloride;
d) barium iodide;
e) silver nitride;
f) zinc fluoride.
1.15. Supply the missing information about the following compounds:
a) SnF2;
e) iron(III) sulfide;
b) FeS;
f) tin(IV) chloride;
c) PbO2;
g) lead(II) oxide;
d) CuBr2;
h) chromium(III) chloride.
1.16. Name the following compounds;
a) ICl3;
b) BrF3;
c) AsCl3;
d) SF4;
e) PCl3;
f) SO3.
1.17. Write correct chemical formulas for the following:
a) chlorine dioxide;
b) silicon tetrafluoride;
c) diboron tetrabromide; d) tricarbon disulfide;
e) iodine pentafluoride; f) tetraphosphorus trisulfide.
1.18. Write the chemical formula of each of the following compounds:
a) dinitrogen tetroxide; b) sulfur hexafluoride;
b) bromine trifluoride; c) tetraphosphorus decoxide;
d) sulfur dioxide;
e) phosphorus pentachloride.
1.19. Give the name of the following compounds:
a) KCl;
b) Na2S;
c) NaI;
e) P4O6;
f) N2O3.
d) SO3;
1.20. Write down the names for the following polyatomic anions:
–1
OH–
NO3–
MnO4–
ClO3–
HCO3–
CH3COO–
IO3–
CN–
–2
SO42–
CO32–
CrO42–
Cr2O72–
C2O42–
SO32–
S2O32–
6
–3
–4
PO43–
Fe(CN)63–
SiO44–
Fe(CN)64–
1.21. Write the correct formula
name them:
a) Al3+ and O2–;
c) Pb2+ and O2–;
e) NH4+ and SO42–;
g) Fe3+ and OH–;
of compounds formed between the following ions,
b) Mg2+ and N3–;
d) NH4+ and CN–;
f) Al3+ and SO42–;
h) Fe2+ and OH–.
1.22. Write the chemical formulas for the following compounds:
a) magnesium nitrate; b) silver nitrate;
c) ammonium chromate; d) potassium phosphate;
e) nickel(II) chlorate;
f) copper(I) bromide;
g) zinc phosphate;
h) chromium(III) sulfate;
i) calcium carbonate;
j) potassium permanganate;
k) lead(II) acetate;
l) aluminum hydroxide.
1.23. Write correct formulas for the following compounds:
a) iron(III) sulfide;
b) mercury(I) acetate;
c) ammonium nitrate; d) calcium bicarbonate;
e) lead(II) chromate;
f) potassium permanganate.
1.24. Write the correct formula of the compounds formed between the corresponding
cations and anions, name them:
Ions
Na+
Ca2+
Al3+
Cl–
O2–
PO43–
SiO32–
OH–
NO3–
1.25. Give the names of the following compounds:
a) CuSO4;
b) Mg3(PO4)2;
c) BaCrO4;
d) K2Cr2O7;
e) S2Cl2;
f) SCl6;
g) SnBr4;
h) Cl2O7;
i) MgSO4·7H2O;
j) CaSO4·2H2O.
1.26. Name the compounds which contain polyatomic ions:
a) NaNO3;
b) SrCO3;
c) Ca3(PO4)3;
d) KClO3;
e) Al2(SO4)3;
f) K2Cr2O7.
1.27. Write the correct names for the following salts:
a) CuI;
b) CuI2;
c) SnCl2;
d) SnCl4;
e) CoSO4;
f) Co2(SO4)3.
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SO42–
S2–
1.28. Write the correct formulas of the compounds formed between the
corresponding cations and anions:
Oxide
Iodide
Phosphate
Permanganate
Sulfide
Hydroxide
Chromate
Carbonate
Sodium
Silver
Zinc
Ammonium
Copper(I)
Iron(II)
Iron(III)
Lead(IV)
Sodium
Silver
Zinc
Ammonium
Copper(I)
Iron(II)
Iron(III)
Lead(IV)
1.29. Supply the missing information for each of the following:
a) PbCrO4;
b) dihydrogen monoxide;
c) (NH4)2Cr2O7;
d) sodium thiosulfate;
.
e) MgCl2 6H2O;
f) potassium ferricyanide;
g) P4O6;
h) sodium sulfate decahydrate;
i) CBr4;
j) phosphorus tribromide.
1.30. Supply the missing information for the following compounds:
a) KMnO4;
b) sodium nitrate;
c) FePO4;
d) silver phosphate;
.
e) FeSO4 7H2O;
f) cobalt(II) sulfate;
g) Si2F6;
h) lead(IV) acetate;
i) Cl2O;
j) potassium carbonate.
1.31. Supply the missing information for the following:
a) (NH4)2SO4;
b) sodium chromate;
c) NaOH;
d) calcium cyanide;
e) Cu3(PO4)2;
f) potassium chlorate;
g) Al2(CO3)3;
h) potassium oxalate;
i) Pb(IO3)2;
j) chromium(III) nitrate.
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2. ATOMIC AND MOLECULAR MASS. MOLE CONCEPT
2.1. The ratio of the mass of oxygen to carbon atom is 1.3329. What is the mass of
the oxygen atom?
2.2. The ratio of the mass of bromine atom to carbon is 6.650. What is the mass of
the bromine atom?
2.3. Calculate the number of moles in each of the following:
a) 3.01x1022 N2 molecules;
b) 4.82x1024 iron atoms.
2.4. Perform the following interconversions of mole and partical number:
a) 6.02x1022 Fe atoms = ? mol Fe atoms;
b) 2 mol O2 molecules = ? O2 molecules;
c) 1.2x1025 H2O molecules = ? mol H2O molecules;
d) 0.25 mol H+ ions = ? H+ ions.
2.5. How many years does it take to evaporate all the molecules in one millimole of
water, if six billion (6x109) water molecules evaporate in each second?
2.6. Answer these questions for 0.25 mol of Al2O3. Find:
a) the number of molecules it contains;
b) the mole number of each kind of atom it contains;
c) the total number of atoms it contains.
2.7. Answer these questions for 2.4x1024 SO3 molecules. Find:
a) its mole number;
b) the number of moles of S and O atoms it contains;
c) the total number of atoms it contains.
2.8. Answer these questions for 26 g of chromium. Calculate:
a) the mole number of atoms it contains;
b) the number of atoms it contains;
c) the mass of a single chromium atom (pay attention to the differences
between atomic mass and the actual mass of an atom).
2.9. How many grams of each of the constituent elements are contained in one mole
of: a) CH4; b) Fe2O3; c) Ca3P2? How many atoms of each element are contained in the
same amount of compound?
2.10. Calculate the number of grams in a mole of each of the following common
substances: a) calcite, CaCO3;
b) quartz, SiO2;
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c) cane sugar, C12H22011;
d) gypsum, CaSO4.2H2O;
e) white lead, Pb(OH)2.
2.11. Calculate the molar mass of each of these compounds:
a) CO2;
b) Ca3(PO4)2;
c) CuSO4·5H2O;
d) Fe(NH4)2(SO4)2 ·6H2O.
2.12. Calculate the molar mass of the following compounds:
a) N2O5;
b) H2SO4; c) Al(OH)3;
d) KAl(SO4)2·12H2O; e) Fe4[Fe(CN)6]3.
2.13. What is the mass of 1.00 mole of each of the following nitrogen compounds:
N2O; NO; NO2; NH3; N2H4; HN3?
2.14. Determine the molar mass for:
a) LiOH; b) H2SO4; c) O2;
d) S8;
e) Ca3SO4; f) K4[Fe(CN)6].
2.15. Perform the following conversions:
a) 3.2 g Cu = ? mol Cu;
b) 0.2 mol Ag = ? g Ag;
c) 3.01x1022 Fe atoms = ? mol Fe atom = ? g Fe;
d) 1 silver atom = ? g;
e) 6.4 g S atom = ? mol S atom = ? S atoms.
2.16. List the following species in order of increasing mass:
a) 1 mol C atom;
b) 1 g of C;
c) 1 carbon atom;
d) 3.01x1023 C atoms.
2.17. Which one of the following is the heaviest?
a) 3.02x1023 Mg atoms;
b) 0.2 mol S atom;
c) 10.8 g of Ag;
d) 1 mol Li.
2.18. How many moles of atoms are contained in:
a) 32.7 g Zn;
b) 7.09 g C1;
c) 95.4 g Cu;
d) 4.31 g Fe;
e) 0.378 g S?
2.19. Calculate, how many moles are represented by:
a) 24.5 g H2SO4;
b) 4.00 g O2.
10
2.20. For the compound Cd(NO3)2⋅4H2O, calculate:
a) how many moles of Cd and of N are contained in 132.4 g of it;
b) how many molecules of water of hydration are in this same amount.
2.21. How many moles and grams of Fe and of S are contained in:
a) 1 mol of FeS2 (pyrite);
b) exactly 1 kg of FeS2.
2.22. A certain public water supply contained 0.10 ppb (part per billion) of
chloroform, CHC13. How many molecules of CHC13 would be contained in a 0.05-mL
drop of this water?
2.23. Find the number of molecules in:
a) 25.0 g of H2O;
b) 1.00 kg of sugar, C12H22O11;
c) 1.00 microgram of NH3;
d) 5.00 mL of CCl4 whose density is 1.594 g/mL.
2.24. Determine the number of molecules in:
a) 50.0 g of mercury;
b) 0.500 kg of glucose C6H12O6;
c) 1.00 nanogram of HCl;
d) 25.0 mL of benzene, C6H6, whose density is 0.879 g/mL.
2.25. Calculate the mole number of each of the following compounds:
a) 15.2 g N2O3;
b) 17.1 g Al2(SO4)3;
c) 87.6 g CaCl2·6H2O.
2.26. Perform the following conversions:
a) 8.8 g NaOH = ? mol NaOH;
b) 0.05 mol Ca3(PO4)2 = ? g Ca3(PO4)2;
c) 2.4x1023 H2O molecules = ? mol H2O = ? g H2O;
d) 17.16 g Na2CO3·10H2O = ? mol Na2CO3·10H2O = ? Na2CO3·10H2O
molecules.
2.27. These problems refer to dinitrogen pentoxide, N2O5.
a) Calculate the molar mass.
b) Find the mass of 1.25 mol N2O5.
c) How many moles of N2O5 are there in 5.4 g of compound?
d) Calculate the mass of compound that contains 0.5 mol of oxygen atom.
e) Calculate the mass of compound that contains 6.4 g of oxygen.
f) Find the mass of N combined with 32 g of oxygen.
11
g) Calculate the number of N atoms in 21.6 g of N2O5.
2.28. Answer the following questions for CO2. Find:
a) its molar mass;
b) the mass of 1.25 mol of CO2;
c) the mole number in 17.6 g of compound;
d) the number of molecules in 6.6 g of CO2;
e) the mass of C combined with 0.25 mol O;
f) the mol number of O combined with 2.4 g C;
g) the number of O atoms in 35.2 g CO2;
h) the number of C atoms combined with 20 oxygen atoms.
2.29. 3 mol mixture of SO2 and CO gases weighs 120 g. Find the mole number of
each gas in the mixture.
2.30. What is the volume of each of the following gases at standard temperature and
pressure (STP)?
a) 9.25 mol SO2;
b) 35.2 g CO2;
c) 1.2x1024 H2 molecules.
2.31. Perform these conversions:
a) 2 mol N2 = ? L (at STP);
b) 6.8 g NH3 = ? L (at STP);
c) 5.6 L O2 at STP = ? mol O2 = ? g O2 = ? O2 molecules;
d) 4.8x1022 H2 molecules = ? mol H2 = ? L H2 = g H2.
2.32. How many atoms of nitrogen are there in 0.1 mol of Ca(NO3)2?
2.33. How many grams of Ca(NO3)2 would you need to get 1.00 gram of calcium?
2.34. What is the mass of (NH4)2SO4 that contains Avogadro's number of hydrogen
atoms?
2.35. How many N2O5 molecules are there in 1.08 g of N2O5?
2.36. How many molecules are there in 5.6 L CO2 at STP?
2.37. How many (a) grams of H2S, (b) moles of H and of S, (c) grams of H and of S,
(d) molecules of H2S are contained in 0.400 mol H2S?
2.38. Answer the following questions for P2O5 that contains 0.62 g of phosphorus.
a) Find the mole number of P2O5.
b) Find the number of molecules of P2O5.
12
c) Find the mass of O in the compound.
d) Find the total number of atoms in the compound.
2.39. 0.02 mol of unknown compound Y2O5 weighs 2.16 g. Calculate:
a) the molar mass of the compound;
b) the atomic mass of the element, Y;
c) the mass of a single Y atom.
2.40. 0.05 mol of an unknown compound X(ClO3)2 is 15.2 g. Find the atomic mass
and the mass of a single X atom.
2.41. 3.42 g X2(SO4)3 contains 0.12 mol of oxygen atoms. What is the atomic mass
of X?
2.42. 104.8 g of Mg3(YO4)2 contains 0.8 mol of Y. What is the atomic mass of Y?
2.43. 35.7 g of Cr2(X2O4)3·6H2O contains 8.1 g H2O. What is the atomic mass of X?
2.44. 10.4 g of X combine with oxygen to form 15.2 g of X2O3. What is the atomic
mass of X?
2.45. When 1.92 g Y is heated with aluminum, 3 g of Al2Y3 are formed. What is the
atomic mass of Y?
2.46. 0.25 mol of CnH2n–2 contains 1.5 mol of H atoms. What is the molar mass of
the compound?
2.47. 0.5 mol compound with a general formula CnH2n+2 contains 3 mol of H. Find
the molar mass of the compound.
2.48. A sample weighing 42.6 g of NX3 occupies 13.44 L at STP. Find the atomic
mass of the element X.
2.49. Find the atomic mass of X in each of the following problems.
a) The mass of a single X atom is 1.5 x 10–23 g.
b) 2.4 x 1023 molecules of XCl2 is 44.4 g.
c) 5.6 L of XH3 at STP is 8.5 g.
d) 0.4 mol PX3 and 0.6 mol PX5 weigh 367 g.
c) 3.84 g Li2SiX6·2H2O contains 0.72 g H2O.
13
3. CALCULATING THE PERCENTAGE BY MASS
3.1. Calculate the percentages of oxygen and hydrogen in water H2O.
3.2. What is the percentage by mass of each element in Al2(SO4)3?
3.3. What are the percentages of boron and water in borax, Na2B4O5(OH)4·8H2O?
3.4. Calculate the percentages of elements K, Fe, C, N, and H2O in
K4[Fe(CN)6]·3H2O crystals.
3.5. Which of these fertilizers has the highest percentage by mass of nitrogen?
a) Urea, N2H4CO.
b) Ammonium nitrate, NH4NO3.
c) Ammonium phosphate (NH4)3PO4.
3.6. Find the percentage by mass of nitrogen in each of the following compounds:
a) N2O;
b) NO;
c) NO2;
d) NH3;
e) N2H4;
f) HN3.
3.7. Find the percentage by mass of sodium and sulfur in the following sodium salts:
a) Na2SO4;
b) Na2S2O3;
c) Na2SO4·10H2O;
d) Na2S2O3·5H2O.
3.8. Determine the percentage composition of potassium carbonate (the percentage
composition = the percentage by mass of each element).
3.9. Calculate the percentage composition of the following compounds:
a) Ca(CN)2;
b) (NH4)2CO3;
c) UO2(NO3)2·6H2O;
d) C16H26O4N2S (penicillin).
3.10. Find the percentage composition of the following compounds:
a) (NH4)2CrO4;
b) PtP2O7;
c) BiONO3·H2O;
d) C21H29O12N7 (streptomycin).
3.11. A sample of a compound contains 18.02 g C, 2.52 g H, 3.50 g N, 4.00 g O and
8.02 g S. What is the percentage by mass of each element in the compound?
3.12. A sample having a mass of 0.924 g was decomposed into its components and
found to have 0.389 g of carbon, 0.059 g of H and 0.476 g of O. Find the percentage
composition of this substance.
3.13. What is the empirical formula of a compound consisting of 7.8 g of potassium,
7.1 g of chlorine and 9.6 g of oxygen?
14
3.14. A borane (containing only B and H) contained 88.45 % B. What is its
empirical formula?
3.15. When 10.24 g of Cu is heated in an atmosphere of oxygen, 11.52 g of an oxide
of copper is produced. What is the empirical formula of the oxide formed?
3.16. A 2.522 g sample of pure caffeine contains 1.248 g of carbon, 0.130 g of
hydrogen, 0.728 g of nitrogen and 0.416 g of oxygen. What is the simplest formula of
caffeine? If the molar mass of caffeine is 194, what is its molecular formula?
3.17. Cocaine is 67.30 % C, 6.98 % H, 21.10 % O, and 4.62 % N. What is the
simplest formula of cocaine?
3.18. What is the simplest formula of the compound that shows the following
analysis: 44.83 % potassium, 18.39 % sulfur, 36.78 % oxygen?
3.19. From the following analytical results (percentage by mass), determine the
empirical formulas for the compounds analyzed:
a) 42.9% C, 57.1% O; b) 77.7% Fe, 22.3% O;
c) 27.3% C, 72.7% O; d) 70.0% Fe, 30.0% O;
e) 53.0% C, 47.0% O; f) 72.4% Fe, 27.6% O.
3.20. Find the empirical formulas of the salts with the following percentage by mass:
a) 40.2% K, 26.9% Cr, 32.9% O;
b) 26.6% K, 35.4% Cr, 38.0% O;
c) 19.3% Na, 26.8% S, 53.9% O;
d) 29.1% Na, 40.5% S, 30.4% O;
e) 32.4% Na, 22.6% S, 45.0% O.
3.21. Determine the empirical formula for each of the compounds:
a) 21.8% Mg, 27.9% P, 50.3% O;
b) 66.8% Ag, 15.9% V, 17.3% O;
c) 79.3% Tl, 9.9% V, 10.8% O;
d) 25.8% P, 26.7% S, 47.5% F;
e) 19.2% P, 2.5% H, 78.3% I;
f) 52.8% Sn, 12.4% Fe, 16.0% C, 18.8% N;
g) 14.2% Ni, 61.3% I, 20.2% N, 4.3% H.
3.22. A compound has the following percentage composition by mass: 58.8 % C, 9.8
% H, and the remainder is oxygen.
a) Calculate the empirical formula of the compound.
b) If 0.2 mol of the compound weighs 40.8 g, find its molecular formula.
15
3.23. What are the empirical formulas of the compounds with the following
composition:
a) 38.71 % C, 16.13 % H, and 45.16 % N;
b) 26.53 % K, 35.37 % Cr, the remainder is oxygen;
c) 21.8 % Mg, 27.8 % P, and 50.3 % O;
d) 79.1 % CaSO4, 20.9 % H2O;
e) 37.7 % Na, 22.95 % Si, the remainder is oxygen.
3.24. A given compound consists of 6.02x1022 atoms of carbon, 1.806x1023 atoms of
hydrogen and 6.02x1022 atoms of oxygen. What is its simplest formula?
3.25. The analysis of a compound showed that it contained 7.2 g carbon, 1.2 mol
hydrogen, and 3.6x1023 atoms of oxygen. What is the molecular formula of the
compound, if its molar mass is 180 g/mol?
3.26. Pyrex glass typically contains 12.9 % B2O3, 2.2 % Al2O3, 3.8% Na2O, 0.4 %
K2O, and 80.7 % SiO2. What is the ratio of silicon to boron atoms in the glass?
3.27. Weighed samples of the following hydrates are heated to drive off the water,
and then the cooled residues are weighed. From the data given, find the formulas of the
hydrates:
a) 0.695 g of CuSO4 ⋅ xH2O gave a residue of 0.445 g;
b) 0.573 g of Hg(NO3)2 ⋅ xH2O gave a residue of 0.558 g;
c) 1.205 g of Pb(C2H3O2)2 ⋅ xH2O gave a residue of 1.032 g;
d) 0.809 g of CoCl2 ⋅ xH2O gave a residue of 0.442 g;
e) 2.515 g of CaSO4 ⋅ xH2O gave a residue of 1.990 g;
f) 0.520 g of NiSO4 ⋅ xH2O gave a residue of 0.306 g;
g) 0.895 g of MnI2 ⋅ xH2O gave a residue of 0.726 g;
h) 0.654 g of MgSO4 ⋅ xH2O gave a residue of 0.320 g;
i) 1.216 g of CdSO4 ⋅ xH2O gave a residue of 0.988 g;
j) 0.783 g of KAl(SO4)2 ⋅ xH2O gave a residue of 0.426 g.
3.28. When 3 g of Mg is burned in excess oxygen, it produces 5 g of magnesium
oxide. What is the empirical formula of the oxide formed?
3.29. When 5.8 grams of silver oxide are decomposed, there remains a silver residue
of 5.4 grams. Calculate the simplest formula of silver oxide.
3.30. The elemental analyses of several compounds are given below. Determine the
empirical formula of each compound whose composition is shown below:
a) 5.6 g Fe and 2.4 g O;
b) 0.64 g S and 0.64 g O;
16
c) 2.82 g K, 2.56 g Cl, 4.62 g O;
d) 18 g C, 1.65 g H, 2.10 g N and 2.4 g O;
e) 4 g Ca, 6.02x1022 C atoms, 0.3 mol O;
f) 2.78 g Co, 11.96 g I, and 4.52 g O.
3.31. A compound with a known molar mass of 28 contains 85.71% carbon and
14.29 % hydrogen. Find its molecular formula.
3.32. A sample of a compound is found to contain 0.97 grams of phosphorus and
1.25 grams of oxygen. If 0.02 mol of this compound weighs 5.68 g, calculate its
molecular formula.
3.33. An element X forms four oxides containing 77.4, 63.2, 69.6, and 72.0 % X. If
the compound with 77.4 % X is XO, what is X, and what are the empirical formulas of
the other compounds?
3.34. A metal forms two different chlorides. Analysis shows one to be 51.1% Cl and
the other to be 64.4% Cl by mass. What are the possible values of the atomic mass of
the metal?
3.35. A metal forms two different chlorides. Analysis shows one to be 40.3% metal
and the other to be 47.4% metal by mass. What are the possible values of the atomic
mass of the metal?
3.36. A sample of an organic compound containing C, H, and O, which weighs
12.13 mg, gives 30.6 mg of CO2 and 5.36 mg of H2O in combustion. The amount of
oxygen in the original samples is obtained by difference. Determine the empirical
formula of this compound.
3.37. An organic compound containing C, H, O, and S is subjected to two analytical
procedures. When a 9.33 mg sample is burned, it gives 19.50 mg of CO2 and 3.99 mg of
H2O. A separate 11.05 mg sample is fused with Na2O2, and the resulting sulfate is
precipitated as BaSO4, which (when washed and dried) weighs 20.4 mg. The amount of
oxygen in the original sample is obtained by difference. Determine the empirical
formula of this compound.
3.38. A 5.135 g sample of impure limestone (CaCO3) yields 2.050 g of CO2 (which
was absorbed in a soda-lime tube) when treated with an excess of acid. Assuming the
limestone is the only component that would yield CO2, calculate the percentage purity
of the limestone sample.
17
4. CONCENTRATION OF SOLUTIONS
4.1. A salt-water solution is prepared by dissolving 20 g NaCl in 230 g of water.
What is the percentage by mass of salt in the solution?
4.2. Calculate the percentage by mass of solute in a solution prepared by dissolving
20 g sugar in 60 g of water.
4.3. Suppose that you have 160 g of a solution that is 20% sugar by mass. Calculate
the percentage concentration of the new solution resulting after:
a) it is mixed with 40 g of water;
b) 32 g of water is evaporated from the original solution;
c) it is mixed with 40 g of sugar;
d) it is mixed with 40 g water and 40 g of sugar;
e) it is mixed with 840 g of a solution containing 5 % sugar.
4.4. Calculate the amount (g) of NaOH in 800 g solution that is 20 % NaOH by
mass.
4.5. Calculate the percentage concentration of the solution resulted by mixing 150 g
solution that is 20% sugar by mass, 50 g solution that is 30 % sugar by mass, 85 g water
and 15 g of sugar.
4.6. How much NaCl must be added to 150 g of 10 % NaCl solution so that the
percentage of NaCl in the resulting solution is 20 %.
4.7. Calculate the masses of 20% and 40% sugar solutions that must be mixed to
obtain 400 g of solution containing 25 % sugar by mass.
4.8. Concentrated nitric acid solution has density of 1.42 g/mL and contains 72%
HNO3 by mass. How many grams of HNO3 are there in 500 mL of this concentrated
solution?
4.9. A student needs 109.5 g of HCl for a reaction. What volume of concentrated
hydrochloric acid solution with a density of 1.2 g/mL and containing 36.5 % HCl by
mass contains 109.5 g of HCl?
4.10. Describe how to prepare 500 mL of 1.5 M Na2SO4 solution.
4.11. 30 g NaOH is dissolved in enough water to form 600 mL of solution. What is
the molarity of the solution?
4.12. 11.2 liters of NH3 gas measured at STP is dissolved in water to prepare 5 liters
of solution. Calculate the molarity of the solution.
18
4.13. Calculate the molarity of the following solutions:
a) 5 L solution containing 2 mol BaCl2;
b) 250 mL solution containing 7 g of KOH;
c) 500 mL solution containing 6.02x1022 NH3 molecules;
d) 500 mL solution containing 28.75 mL C2H5OH (d = 0.8 g/mL);
e) 600 mL solution containing 6.72 L HCl measured at STP;
f) 1250 mL solution containing 42.5 g of NaNO3 sample that is 80% pure.
4.14. How many grams of Fe(NO3)2 are required to make 400 mL of a solution with
concentration 0.5 M Fe(NO3)2?
4.15. How many liters of 3 M NaOH solution can be prepared with 360g NaOH?
4.16. Describe how to prepare 0.2000 M CuSO4, starting with solid CuSO4⋅5H2O.
4.17. Tell how you would prepare each of the following solutions:
a) 3.00 liters of 0.750 M NaCl from solid NaCl;
b) 55.0 mL of 2.00 M ZnSO4 from solid ZnSO4⋅7H2O;
c) 180 mL of 0.100 M Ba(NO3)2 from solid Ba(NO3)2;
d) 12 liters of 6.0 M KOH from solid KOH;
e) 730 mL of 0.0700 M Fe(NO3)3 from solid Fe(NO3)3⋅9H2O.
4.18. Tell how you would prepare each of the following solutions:
a) 125 mL of 0.62 M NH4Cl from solid NH4Cl;
b) 2.75 liters of 1.72 M Ni(NO3)2 from solid Ni(NO3)2⋅6H2O;
c) 65.0 mL of 0.25 M Al(NO3)3 from solid Al(NO3)3⋅9H2O;
d) 230 mL of 0.460 M LiOH from solid LiOH;
e) 7.57 liters of 1.10 M KCr(SO4)2 from solid KCr(SO4)2⋅12H2O.
4.19. 500 mL of water are added to 300 mL of 0.4 M H2SO4 solution. Find the
molarity of the resulting solution.
4.20. 100 mL of 6 M HCl solution is diluted to 600 mL. What is the molar
concentration of the final solution?
4.21. What volume of water must be added to 200 mL of 3 M BaCl2 solution to
obtain 1 M solution?
4.22. How many mL of water must be evaporated from 500 mL of 0.3M NaCl
solution so that the concentration of NaCl becomes 0.5 M?
19
4.23. Describe how you would prepare 2 L of 0.7 M HNO3 solution, starting with a
concentrated HNO3 solution that has a density of 1.4 g/mL and contains 63 % HNO3 by
mass.
4.24. Commercial concentrated sulfuric acid is labeled as being 96.0% H2SO4 by
mass and having a density of 1.84 g/mL. Calculate the molarity of this solution.
4.25. The density of a 3.68 M sodium thiosulfate solution is 1.269 g/mL. Find the
percentage of Na2S2O3 by mass.
4.26. The density of a 1.660 M Na2Cr2O7 solution is 1.244 g/mL.
a) Find the percentage of Na2Cr2O7 by mass.
b) If 1.50 liters of water are added to 1.0 liter of this solution, what is the
percentage by mass of Na2Cr2O7 in the new solution?
4.27. The density of a 2.04 M Cd(NO3)2 solution is 1.382 g/mL. If 500 mL of water
is added to 750 mL of this solution, what will be the percentage by mass of Cd(NO3)2 in
the new solution?
4.28. How many mL of 0.5 M H2SO4 solution can be prepared from 20 mL of 2.5 M
H2SO4 solution?
4.29. A 300 mL of 0.2 M HNO3 solution is added to 200 mL of 0.15 M HNO3
solution. Calculate the molarity of the resulting solution.
4.25. 400 mL of 0.6 M KCl solution is added to 600 mL of 0.2 M KCl solution.
What is the molarity of the final solution?
4.26. If 500 mL of 3.00 M H2SO4 is added to 1.50 liters of 0.500 M H2SO4, what is
the resulting concentration?
4.27. What volumes of 2 M and 6 M solutions of HCl should be mixed to prepare
500 mL of a 3 M solution? Disregard the change in the volume in mixing.
4.28. What volumes of 4 M and 6 M KNO3 solutions should be mixed to obtain a
500 mL of 4.8 M KNO3 solution?
4.29. 3.1 g MgX2 is used to prepare 500 mL of 0.1 M MgX2 solution. What is the
atomic mass of X?
4.30. 19.36 g of X(NO3)3 is used in the preparation of 400 mL of 0.2 M solution.
Calculate the atomic mass of X.
20
5. BALANCING CHEMICAL EQUATIONS
5.1. In laboratory, oxygen gas may be generated by decomposing potassium chlorate
(KClO3) into potassium chloride and oxygen gas. Write a balanced equation describing
the reaction.
5.2. Water that contains dissolved calcium compounds is called "hard" water. One
way to "soften" such water is to add sodium carbonate, Na2CO3. It removes the calcium
by forming calcium carbonate, which is insoluble in water. Balance the equation that
illustrates the reaction.
5.3. Consider the combustion of amyl alcohol, C5H11OH.
a) How many moles of O2 are needed for the combustion of 1 mole of amyl
alcohol?
b) How many moles of H2O are formed for each mole of O2 consumed?
c) How many moles of CO2 are produced for each mole of amyl alcohol
burned?
5.4. Balance each of the following equations:
a) CH4 + Cl2 → CCl4 + HCl;
b) C2H6 + O2 → CO2 + H2O;
c) Al(OH)3 + H2SO4 → Al2(SO4)3 + H2O;
d) P2H4 → PH3 + P4;
e) Fe + H2O → Fe3O4 + H2;
f) S2Cl2 + NH3 → N4S4 + NH4Cl + S8;
g) Al4C3 + HCl → AlCl3 + CH4;
h) Ag + HNO3 → AgNO3 + NO + H2O.
5.5. Balance the following equations:
a) C2H4(OH)2 + O2 → CO2 + H2O;
b) Li + H2O → LiOH + H2;
c) Ba(OH)2 + AlCl3 → BaCl2 + Al(OH)3;
d) KHC8H4O4 + KOH → K2C8H4O4 + H2O;
e) (NH4)2Cr2O7 → N2 + Cr2O3 + H2O.
5.6. What is the molecular formula of the compound represented by X in the
following balanced equation?
4 X + 5 O2 = 4 NO + 6 H2O
5.7. Determine the formula of X in the following balanced equations:
a) 9 Fe2O3 + 2 NH3 = 6 X + N2 + 3 H2O;
b) 2 MnO2 + 4 X + O2 = 2 K2MnO4 + 2 H2O;
c) 2 KMnO4 + 16 HCl = 2 MnCl2 + 2 KCl + 5 X + 8 H2O;
21
d) Cr2O3 + 3 X = 2 CrCl3 + 3 CCl2O;
e) As2S3 + 12 NaNO3 + 3 Na2CO3 =
= X + 3 Na2SO4 + 3 CO2 + 12 NaNO2.
5.6. Predict the products of the following reactions and balance the equations:
a) HCl + Mg(OH)2 → …
b) PbCl2 + K2SO4 → …
c) CH3CH2OH + O2 → …
d) Fe + AgNO3 → …
5.7. Given that the oxidation state of hydrogen is “+1”, of oxygen “–2”, and of
fluorine “–1”, determine the oxidation states of the other elements in:
a) NaF;
b) H2SiO3; c) PH3;
d) H2S;
e) CrF3;
f) H2SO4;
g) H2SO3; h) Al2O3; i) HPO42–.
5.8. Determine the oxidation number of the central atom in:
a) K4P2O7; b) NaAuCl4;
c) Na5HV10O28;
d) ICl;
e) Ba2XeO6;
f) Ca(ClO2)2.
5.9. Find the oxidation number of each atom in the following molecules and ions:
a) CO2;
b) AgNO3;
c) BaO2;
d) LiH;
e) Ca2P2O7;
f) C2O42–;
g) PCl62–; h) B4O72–;
i) UO22+.
5.10. Find the oxidation number of each atom in the following molecules and ions:
a) SO3;
b) H2SO3;
c) Zn(IO3)2;
d) Na2O2; e) (NH4)2PO4;
f) V2O72–;
g) BiO+;
h) SiO32–;
i) S2O32–.
5.11. Write balanced ionic half-reactions for the oxidation of each of the following
reducing agents in acid solution:
a) Sn;
b) H2C2O4;
c) Br–;
d) Sn2+;
e) H2S;
f) Ba;
g) Al;
h) HNO2;
i) Hg22+;
j) I–;
k) H3AsO3;
l) H2O2.
5.12. Write balanced ionic half-reaction equations for the reduction of each of the
following oxidizing agents in acid solution:
a) Co3+’
b) PbO2;
c) ClO4–; d) F2;
e) Ag+;
f) NO3–;
g) BrO–;
h) Sn2+;
i) MnO2; j) ClO2–;
k) H2O2;
l) Cr2O72–;
m) IO3–;
n) Br2;
o) Fe2+;
p) Cd2+.
22
5.13. Balance the oxidation-reduction equations:
a) NaBr + Cl2 → NaCl + Br2;
b) Sn + O2 + HCl → SnCl2 + H2O;
c) FeCl2 + H2O2 + HCl → FeCl3 + H2O.
5.14. Balance the oxidation-reduction equation for the oxidation of H2S by HNO3 to
produce NO and S in aqueous acidic solution (thus H+ and H2O may be involved).
5.15. Balance the oxidation-reduction equation for the oxidation of FeCl2 by
Na2Cr2O7 to give CrCl3 and FeCl3 in aqueous acidic solution.
5.16. Balance the oxidation-reduction equation for the oxidation of Zn by NaNO3 to
produce Na2Zn(OH)4 and NH3 in basic aqueous solution.
5.17. Balance the following equations, describing oxidation by nitric acid:
a) Cu + HNO3 (conc.) → Cu(NO3)2 + NO2 + H2O;
b) Cu + HNO3 (dilute) → Cu(NO3)2 + NO + H2O;
c) Zn + HNO3 (dilute) → Zn(NO3)2 + NH4NO3 + H2O;
d) CuS + HNO3 → Cu(NO3)2 + S + NO + H2O;
e) As2S5 + HNO3 → H3AsO4 + H2SO4 + NO2.
5.18. Balance the following skeleton equations (acidic aqueous solutions), complete
molecular reactions:
a) MnO + PbO2 → MnO4– + Pb2+;
b) C2O42– + MnO4– → CO2 + Mn2+;
c) H2O2 + MnO4– → Mn2+ + H2O.
5.19. Balance the following equations (basic aqueous solutions):
a) Bi2O3 + NaOH + NaOCl → NaBiO3 + NaCl;
b) Fe(CN)63– + Cr2O3 → Fe(CN)64– + CrO42–;
c) CrI3 + Cl2 → CrO42– + IO4– + Cl–;
d) Ag + CN– + O2 → Ag(CN)2– + OH–;
e) Co2+ + Na2O2 → Co(OH)3↓.
5.20. Balance the following equations (no water involved):
a) NaN3 → Na3N + N2;
b) Ca3PO4 + SiO2 + C → CaSiO3 + P4 + CO;
c) P2H4 → PH3 + P4H2.
5.21. Write balanced equations for the reaction that occurs between metallic zinc
and dilute nitric acid to produce ammonium nitrate as one of the products.
23
5.22. When sodium thiosulfate, Na2S2O3, interacts with iodine in quantitative
analysis, one of the products is sodium tetrathionate, Na2S4O6. Write the complete
equation and balance it.
5.23. A sample of potassium iodide contains some potassium iodate as impurity.
When sulfuric acid is added to a solution of this sample, iodine is produced. Give the
equation for the formation of the iodine.
5.24. When copper is heated in concentrated sulfuric acid, an odor of sulfur dioxide
is noted. Write the chemical equation; balance it.
5.25. A classical operation in quantitative analysis is the use of a Jones reductor, a
column of granulated zinc. A solution of ferric (Fe3+) salts is passed through this column
prior to titration with potassium permanganate. Give the equation for the reaction in the
column.
5.26. Pure hydroiodic acid (HI) cannot be prepared by adding concentrated sulfuric
acid to sodium iodide and distilling off the hydroiodic acid, because of side reactions.
One side reaction yields hydrogen sulfide, as noted by the odor. Give the equation for
this side reaction.
5.27. Write the balanced equation for the reaction that occur when chlorine gas is
bubbled through a solution of iron(II) bromide.
5.28. In the final step of producing bromine from sea water, a mixture of sodium
bromide and sodium bromate is treated with sulfuric acid. Give the equation for the
reaction; balance it.
5.29. A microchemical procedure uses a cadmium amalgam (cadmium dissolved in
metallic mercury) to reduce iron salts to their lowest oxidation state prior to titration
with standard solution. Give the equation for the reaction involving the cadmium.
5.30. When zinc is heated with concentrated sulfuric acid, hydrogen sulfide is
evolved. Write the chemical reaction; balance it.
5.31. The Marsh test for the detection of arsenic depends on the reaction of an
arsenic compound, such as H3AsO4, with metallic zinc in acid solution. The arsenic is
liberated as arsine, AsH3, which may be decomposed by heat to give an "arsenic
mirror". Write the balanced equation for the reaction that occurs in the case of the
arsenic-positive test.
24
6. CALCULATIONS BASED ON CHEMICAL EQUATIONS
6.1. When mercury oxide, HgO, is heated, it releases mercury and oxygen gas. How
many moles of oxygen gas will be produced from the decomposition of 4 mol of
mercury oxide?
6.2. How many molecules of potassium chlorate are required in the preparation of 6
mol of oxygen gas?
6.3. When aluminum is heated with sulfur, aluminum sulfide is formed.
a) Write the balanced equation.
b) Calculate the number of moles of aluminum that combines with 6 mol of
sulfur.
c) Calculate the number of aluminum sulfide molecules produced from 0.4
mol of Al.
6.4. If 212 grams of sodium carbonate react with calcium hydroxide, how many
grams of sodium hydroxide are formed?
6.5. How many grams of sodium hydroxide will react with 49 g of phosphoric acid?
6.6. How many liters of oxygen (at STP) are liberated by heating 490 g of potassium
chlorate?
6.7. Consider the reaction
MnO2 + 4 HCl → MnCl2 + Cl2 + 2 H2O.
How many grams of MnO2 are required to produce 5.6 L of Cl2 at STP?
6.8. If 152 mL of liquid carbon disulfide (density 1.25 g/mL) are burned completely:
a) how many liters of SO2 at STP are formed?
b) how many liters of O2 are required at STP?
6.9. How many liters of carbon dioxide are formed from the combustion of 60 liters
of ethylene gas, C2H4? Recall that the combustion of any compound made from C and H
elements produces carbon dioxide and water vapor.
6.10. Given the balanced equation N2 + 3 H2 = 2 NH3, calculate (assuming that all
volume measurements are made under identical conditions):
a) the volume of H2 that reacts with 12 L of N2;
b) the volume of N2 that reacts with 12 L of H2;
c) the volume of NH3 produced from 4 L of N2;
d) the volumes of N2 and H2 to produce 60 L of NH3;
25
6.11. Aluminum reacts with hydrochloric acid and produces aluminum chloride and
hydrogen gas. Answer the following questions for 2.7 g of aluminum used in the
reaction.
a) How many grams of AlCl3 will be produced?
b) How many moles of HCl are used?
c) How many molecules of H2 are formed?
6.12. The combustion of ammonia, NH3, produces NO and H2O.
a) Write the balanced equation representing the reaction.
b) How many moles of H2O are produced when 2 mol of NH3 is burned?
c) How many moles of O2 are required to react completely with 3 mol of
NH3?
d) How many grams of NO are produced when 16 grams of O2 are used?
e) How many grams of H2O are formed when 8.96 L of NH3 at STP is
completely burned?
f) How many liters of NO at STP will be produced when 1.8x2023 NH3
molecules are burned?
g) How many liters of O2 and how many liters of air are required to burn
20 L of NH3?
(Assume the identical conditions. Recall that 1/5 of air is O2 by volume.)
6.13. A portable hydrogen generator utilizes the reaction:
CaH2 + 2 H2O → Ca(OH)2 + 2 H2↑.
How many grams of H2 can be produced by 50 g of CaH2?
6.14. How much iron(III) oxide can be produced from 6.76 g of FeCl3·6H2O by the
following reactions?
FeCl3·6H2O + 3 NH3 = Fe(OH)3 + 3 NH4Cl + 3 H2O;
2 Fe(OH)3 = Fe2O3 + 3 H2O.
6.15. In a rocket motor fueled with butane, C4H10, how many kilograms of liquid
oxygen should be provided with each kilogram of butane to provide for complete
combustion?
6.16. Ethyl alcohol, C2H5OH, can be made by the fermentation of glucose, C6H12O6,
as indicated by the (unbalanced) equation:
C6H12O6 → C2H5OH + CO2.
How many metric tons of alcohol can be made from 2.00 metric tons of glucose?
6.17. In the Mond process for purifying nickel, the volatile nickel carbonyl,
Ni(CO)4, is produced by the reaction:
Ni + 4 CO = Ni(CO)4.
How much CO is used in volatilizing each kilogram of nickel?
26
6.18. The mixture of 2 mol of H2 and 2 mol of O2 gases are ignited to obtain water.
Which reactant is limiting? Which is the excess reactant? How much water will be
produced?
6.19. A mixture of 100 g Al and 200 g MnO was heated to initiate the reaction:
2 Al + 3 MnO = Al2O3 + 3 Mn.
Which initial substance remained in excess? How much?
6.20. Carborundum, SiC, is used as an abrasive. It is formed by the combination of
SiO2 and carbon, according to the reaction:
SiO2 + 3 C = SiC + 2 CO.
What mass of SiC is formed from 6 grams of SiO2 and 6 grams of C?
6.21. How many grams of water are produced when 4 g of H2 and 8 g of O2 are
reacted?
6.22. Given: N2 + 3 H2 = 2 NH3. If 20 L of N2 and 15 L of H2 gases at the same
conditions are reacted, which gas will be excess and how many liters?
6.23. Given: N2 + 3 H2 = 2 NH3. 3.01x1023 molecules of nitrogen and 3.36 L of H2
at STP are reacted. How many grams of NH3 are produced?
6.24. Aluminum and hydrogen bromide react according to the following reaction:
2 Al + 6 HBr = 2 AlBr3 + 3 H2.
If 4 mol of Al and 9 mol of HBr are allowed to react,
a) which of the two reactants is the limiting one?
b) how many moles of the excess reactant are left at the end of reaction?
c) what is the maximum mole number of H2 obtained?
6.25. 18 g of C and 8 g of oxygen are reacted to form CO2. Which element and how
many grams remain behind?
6.26. Given: the reaction 2 H2S + 3 O2 = 2 H2O + 2 SO2. The quantities of
reactants are given below. For each of the following, determine the excess reactant and
the maximum grams of water produced.
a) 2 mol of H2S and 4 mol of O2;
b) 4 mol of H2S and 6 mol of O2;
c) 8.5 g of H2S and 9.6 g of O2;
d) 6.02x1022 H2S molecules and 6.72 L O2 at STP;
e) 4.48 L H2S at STP and 19.2 g O2;
f) 17.92 L H2S at STP and 13.44 L O2 at STP.
6.27. Given the reaction: As4O6 + 4 I2 + 4 H2O = 2 As2O5 + 8 HI. What is the
maximum grams of HI produced if 2 mol of each of the reactants are reacted?
27
6.28. Nitric oxide, NO, is prepared according to the following reaction in
laboratories: 3 KNO2 + KNO3 + Cr2O3 = 4 NO + 2 K2CrO4. Calculate the
maximum liters of NO at STP produced by the reaction of 100 g of each of the
reactants.
6.29. Equal weights of sodium and chlorine gas are reacted in a closed container to
give 0.1 mol of sodium chloride. Which element will remain behind and how many
grams?
6.30. Equal moles of aluminum and oxygen are reacted to give 20.4 g of aluminum
oxide. Which one remains unreacted and how many moles?
6.31. Equal volumes of sulfur dioxide and oxygen gases are reacted to give 5 liters
of sulfur trioxide at the same conditions. Which one remains unreacted and how many
liters?
6.32. A mixture of 1 ton of CS2 and 2 tons of Cl2 is passed through a hot reaction
tube, where the following reaction takes place:
CS2 + 3 Cl2 → CCl4 + S2Cl2.
a) How much CCl4 can be made by complete reaction of the limiting starting
material?
b) Which starting material is in excess, and how much of it remains unreacted?
6.33. What mass of Cu2S can be produced from the reaction of 100 g copper with
50 g of sulfur?
6.34. What weight of HCl is produced when sulfuric acid reacts with 200 grams of
87.75% pure sodium chloride (assume that 12.25% of the sample is inert in the
reaction)?
6.35. How many liters (at STP) of oxygen can be liberated from 1700 grams of a
solution which is 3.0% hydrogen peroxide by mass? The equation is:
2 H2O2 → 2 H2O + O2↑.
6.36. How many grams of H2SO4 can be produced from 300 g of FeS2 which is 60 %
pure by weight?
6.37. How many grams of sodium chloride that is 90 % pure are required to produce
73 g of HCl according to the reaction with H2SO4?
6.38. A 25 g sample of iron reacts with 200 g of 14.6 % HCl solution by mass. The
reaction is: Fe + 2 HCl = FeCl2 + H2. Calculate the percentage of iron in the sample.
(Assume the impurities are inert to HCl.)
28
6.39. When an unknown quantity of magnesium is reacted with HCl, 4.48 L of H2 at
STP together with some magnesium chloride are formed.
a) What mass of magnesium chloride is formed?
b) If the sample of magnesium is 96 % pure, what mass of magnesium sample is
used in the reaction?
c) What mass of HCl solution that is 20 % HCl by mass would it be required to
produce 4.48 L of H2 at STP?
6.40. When 20 g of iron is reacted with oxygen, 20 g of iron(III) oxide is formed.
What percentage of iron is reacted with oxygen?
6.41. The acetylene gas, C2H2, is an important raw material in the production of
many chemicals, such as synthetic rubber, alcohol, etc. It may be prepared from
limestone (CaCO3), coke (C) and water according to the following reactions:
I. CaCO3 → CaO + CO2;
II. CaO + 3 C → CaC2 + CO;
III. CaC2 + H2O → C2H2 + Ca(OH)2.
Assuming an excess of all other reactants, how many liters of C2H2 at STP can be
obtained from 50 g CaCO3.
6.42. KBrO4 may be prepared by the following series of reactions:
I. Br2 + 2 KOH → KBr + KBrO + H2O;
II. 3 KBrO → 2 KBr + KBrO3;
III. 4 KBrO3 → 3 KBrO4 + KBr.
Assuming the excess KOH, how much Br2 in grams is needed to prepare 109.8 g
KBrO4 by the above sequence of reactions?
6.43. Given the reactions:
I. Al4C3 + 12 H2O = 4 Al(OH)3 + 3 CH4;
II. CH4 + 2 O2 = CO2 + 2 H2O.
The methane gas that is obtained from 50 g impure sample of Al4C3 is required 38.4
g of O2 to be completely burned. What is the percentage purity of Al4C3 in the impure
sample?
6.44. Iron is prepared in the blast furnace according to the sequence of these
reactions:
I. 2 C + O2 = 2 CO;
II. 3 CO + Fe2O3 = 2 Fe + 3 CO2.
Assuming the excess of O2, how many tons of iron can be obtained by the reaction
of 5 tons of hematite or Fe2O3, that is 80 % pure, with 1 ton of coke?
6.45. To burn 30 liters of a mixture of C3H4 and C3H8 gases at STP, 140 liters of O2
are needed at the same conditions. Calculate the volume of C3H4 in the mixture.
29
6.46. The complete combustion of a 13.44 L mixture of C2H4 and C3H4 gases at STP
produces 31.36 L CO2 under the same conditions. Find the mole number of each gas in
the mixture.
6.47. 11.9 g of an alloy made from Al and Zn is reacted with sufficient amount of
HCl and 8.96 L of H2 at STP are produced. What is the amount of Al in the alloy?
6.48. A 20 g alloy of Mg and Al elements is reacted with HCl and 24.64 L of H2 at
STP are produced. Find the percentage by mass of Al in the mixture. Both metals react
with HCl and produce metal chlorides and hydrogen gas.
6.49. Both sodium and calcium metals react with water to produce metal hydroxides
and H2 gas. If 4 moles of H2 are obtained from 5 moles of the mixture of sodium and
calcium metals, calculate the mole percentage of sodium in the mixture.
6.50. When 2.2 g of a compound containing carbon and hydrogen is burned, 3.36
liters of CO2 at STP are produced. What is the empirical formula of the compound?
6.51. The complete combustion of 8 g of compound made from only C and H
produced 26.4 g CO2. What is the empirical formula of the compound?
6.52. When 2.3 g of a compound containing C, H and O is burned completely, 4.4 g
of CO2 and 2.7 g of H2O are produced. Find its empirical formula.
6.53. When 1.76 g of a compound containing C, H and O is burned completely in
oxygen, 3.52 g of CO2 and 1.44 g of H2O are produced.
a) Calculate the empirical formula of the compound.
b) If 0.05 mol of the compound is 4.4 g, what is the molecular formula of
the compound?
6.54. Copper(II) nitrate is prepared by dissolving a weighed amount of copper metal
in a nitric acid solution:
3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2 NO↑ + 4 H2O.
What volume of 6.00 M HNO3 should be used to prepare 10.0 g of Cu(NO3)2?
6.55. The preparative task is to precipitate all the Ag+ from 50 mL of 0.12 M AgNO3
solution. Answer the following questions.
a) What weight of AgCl can be obtainedl?
b) What weight of NaCl is required to precipitate the AgCl?
c) What volume of 0.24 M HCl would be needed for the task?
6.56. How many milligrams of Na2CO3 will react with 45.00 mL of 0.2500 M HCl?
30
6.57. What weight of silver and what volume of 6.00 M HNO3 are needed for the
preparation of 500 mL of 3.00 M AgNO3?
6.58. How many tons of limestone (CaCO3) are needed to prepare 5.00 tons of dry
ice (CO2), assuming that 30% of the CO2 produced is wasted in converting it to the
solid?
6.59. What volume of commercial HCl (36% HCl by mass, density = 1.18 g/mL)
and what weight of limestone (90% pure) are needed to produce 2.00 kg of CO2?
6.60. What volume of commercial HCl (36% HCl by mass, density = 1.18 g/mL)
and what weight of pyrolusite (85% MnO2) are needed to produce 5.00 kg of Cl2?
6.61. How many grams of 95% pure NaCl are needed to produce 2.00 kg of HCl?
6.62. Commercial sulfuric acid that has a density of 1.84 g/mL and is 95% H2SO4 by
mass is used for the production of 365 g of HCl. What mass and volume of commercial
acid is needed?
6.63. A manufacturer supplies 1 kg cans of calcium carbide whose purity is labeled
as 85%. What volume of acetylene can be prepared from 1 kg of this product if the label
is correct?
6.64. How many grams of sand, SiO2, are needed to prepare 1 kg of SiF4, assuming
that 25% of the sand is inert material and does not produce SiF4? What volume of SiF4
is obtained, measured at STP?
REFERENCES
1. Dictionary of Chemistry. – McGraw-Hill Inc., 2003. – 443 p.
2. Hoenig, Steven L. Basic Training in Chemistry. – Kluwer Academic
Publishers, 2002. – 184 p.
3. Rosenberg, Jerome L., Epstein, Lawrence M. College Chemistry. –
McGraw-Hill Companies, Inc., 2000. – 154 p.
4. Rosenberg, Jerome L., Epstein, Lawrence M. Theory and Problems of
College Chemistry. – McGraw-Hill Companies, Inc., 1997. – 386 p.
5. Smith, Robert Nelson, Pierce, Conway. Solving General Chemistry
Problems. – W.H.Freeman & Company., 1980. – 474 p.
6. Williams, Linda. Chemistry Demystified. – McGraw-Hill Companies, Inc.,
2003. – 280 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]
B
Be
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
Nitrogen
Carbon
14.0067
6
12.011 7
P
Si
Phosphorus
Silicon
30.974
14
28.085 15
Ti
V
Titanium
Vanadium
22
47.90 23
50.94
As
Ge
Arsenic
Germanium
74.92
32
72.59 33
Zr
Nb
Zirconium
Niobium
40
91.22 41
92.906
Sn
Sb
Tin
Antimony
50
118.69 51
121.75
Hf
Ta
Hafnium
Tantalum
La–Lu
72
178.49 73
180.95
Bi
Pb
Tl
Bismuth
Lead
Thallium
208.98
207.2 83
81
204.3 82
Rf
Db
Rutherfordium
Dubnium
Ac–(Lr)
104
[261] 105
[262]
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
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]
OF CHEMICAL ELEMENTS
VI
Appendix 1
VII
VIII
(H)
O
F
Fluorine
Oxygen
18.998
8
15.999 9
Cl
S
Chlorine
Sulfur
35.453
16
32.06 17
Cr
Mn
Chromium
Manganese
24
51.996 25
54.938
Br
Se
Bromine
Selenium
79.904
34
78.96 35
Mo
Tc
Molybdenum
Technetium
42
95.94 43
98.906
Te
I
Tellurium
Iodine
52
127.6 53
126.90
W
Re
Tungsten
Rhenium
74
183.8 75
186.21
At
Po
Astatine
Polonium
[210]
84
[209] 85
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
Co
Ni
Cobalt
Nickel
27
58.933 28
58.70
Kr
Krypton
36
83.80
Rh
Pd
Rhodium
Palladium
45
102.9 46
106.4
Xe
Xenon
54
131.3
Ir
Pt
Iridium
Platinum
77
199.2 78
195.1
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
ХИМИЯ НА АНГЛИЙСКОМ ЯЗЫКЕ
Модуль 1
БАЗОВЫЕ ХИМИЧЕСКИЕ ПОНЯТИЯ
Учебное пособие
38