CHM13P Multiple Choice Identify the choice that best completes the statement or answers the question.
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1. What is the molecular formula for hydrogen chloride? a. HClO2 c. HClO3 b. HCl d. HClO4 2. A co compou mpound nd con contains ains sul sulfur, fur, oxyg oxygen en,, an and ch chlori lorin ne. Analy nalyssis shows hows that hat it it con conta tain inss by by mas masss 26 26.95 .95% sulfur and 59.61% chlorine. What is the simplest formula for this compound? a. S2OCl2 c. SOCl2 b. SOCl d. SO2Cl2 3. A 4.6 4.628 28-g -g samp sample le of an an ox oxide ide of of iro iron n was fou found to con contain ain 3.3 3.34 48 g of iro iron n an and 1.2 1.280 g of of ox oxygen ygen.. What is simplest formula for this compound? a. FeO c. Fe2O3 b. Fe3O4 d. Fe3O2 4. What mass of FeCl 3 would contain the same total number of ions as 16.8 g of Al 2(SO4)3? a. 10.8 g c. 7.96 g b. 9.95 g d. 8.01 g 5. A sam sampl plee of of lea lead d ore ore has has a den density sity of 8.80 .80 g/ g/mL. mL. It It is is com compo possed of tw two lea lead d com compo poun unds ds:: lea lead d ox oxide ide, PbO (density 9.10 g/mL) and lead selenide, PbS (density 8.10 g/mL). What is the percent of the ore is lead oxide? a. 89.0 % c. 96.7 % b. 92.0 % d. 70.0 % 6. The empirical formula of a compound is CHBr and its molecular weight is 185. What is its molecular formula? (atomic weights: C = 12.01, H = 1.008, Br = 79.90) a. CH2Br c. C3H3Br 3 b. C2H2Br 2 d. C2HBr 7. Bala Balan ncing ing a che chemica micall equ equat atio ion n so tha that it it ob obeys eys th the law law of cons conseervat rvatio ion n of of mat mattter requ equires ires:: a. Changing Changing the formulas formulas of the the product productss and and reactant reactants. s. b. Adjustin Adjusting g the coefficien coefficients ts in front front of the formulas formulas so there there are the same same number number and type of atom on both sides of the equation. c. Keeping Keeping the the total total charge charge the same on both sides sides of of the equatio equation. n. d. Making Making sure sure the reactan reactants ts and products products are are in the the same phase. phase. 8. How many molecules of O 2 would react with 56 C 2H6 molecules according to the following balanced equation? 2C2H6 + 7O2 → 4CO2 + 6H2O a. 112 c. 196 b. 784 d. 50 9. What volume of 0.130 M HCl solution will just react with 0.424 gram of Ba(OH) 2? 2HCl + Ba(OH)2 → BaCl2 + 2H2O a. 38.1 mL c. 32.6 mL b. 24.1 mL d. 18.6 mL 10. Which one of the following is an alkaline earth metal? a. bismuth, Bi c. magnesium, Mg b. tin, Sn d. potassium, K 11. Which one of th the following is a strong electrolyte? a. HNO3 c. HNO2 b. CH3COOH d. NH3 12. Determin mine the oxidation number of of th the underlined eleme ement in Li LiAlH 4. a. + 2 c. + 1 −1 0 d. 13. Determin mine the oxidation number of the underlined eleme ement in H 2P2O7. a. + 6 c. + 4 b. + 5 d. + 3 14. When two nonmetals combine, ____. a. they they form form a bin binary ary ionic ionic compou compound nd.. b. they neutralize neutralize the acid formed in the the reaction reaction.. c. they they form form a binary binary cova covalen lentt compo compound und.. d. they they rel releas easee hydr hydrog ogen en gas gas.. 15. Which of the following rea reactions is a decom composition reaction? a. c. 2KClO3(s) → 2KCl(s) + 3O2(g) C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O( ) b. Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) d. 2H2(g) + O2(g) → 2H2O( )
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16. What ions are almost completely rem removed from solution when 0.1 M aqueous solutions of HBr and Pb(CH3COO) 2 are mixed? Choose the response that includes all the ions removed. H+ Br- Pb2+ CH3COO-
I. II. III. IV.
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a. II, III and IV c. III and IV b. I, II, III and IV d. II and III 17. The mass number of an atom is is the number of ____ in the atom. a. neutrons c. electrons plus the number of neutrons b. protons pl plus th the nu numbe mber of of ne neutrons d. protons pl plus th the nu number of of el electrons 90 18. Give th the nu number of pr protons, neutrons, and electron rons in an atom of of the Sr isotope. a. 90 p, 38 n, 90 e c. 38 p, 52 n, 38 e b. 52 p, 38 n, 52 e d. 38 p, 90 n, 38 e 19. A hypothetical element consists of four isotopes having the following percentage natural abundance and isotopic masses. What is its atomic weight? isotope 1: 16.06% (52.100 amu); isotope 2: 28.36% (53.097 amu); isotope 3: 42.60% (54.093 amu); isotope 4: 12.98% (55.090 amu). a. 53.262 amu c. 53.487 amu b. 53.314 amu d. 53.620 amu 20. 20. The The fiv fivee iso isoto tope pess of of nic nicke kell occ occur ur in the the fol follo lowi wing ng perc percen enta tage gess wit with h the the foll follow owin ing g iso isoto topi picc mas masse ses. s. The atomic weight is 58.69 amu. What is the isotopic mass of 60Ni? (Choose the closest answer.) Isotope 58Ni 60Ni 61Ni 62Ni 64Ni
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Mass (amu) 57.935 ? 60.931 61.928 63.928
% 68.27 26.10 1.13 3.59 0.91
a. 59.93 amu c. 60.57 amu b. 59.31 amu d. 58.62 amu 21. 21. Which hich res respon ponse lists ists all all th the tru truee stat statem emen ents ts abou aboutt the the fou four quan quantu tum m nu number mberss?
n = principal quantum number, l = angular momentum quantum number, ml = magnetic quantum number, m s = spin quantum number,
I. II. III. IV.
n = 1,2,3, . . . l = 0,1,2,3, . . ., (n − 1) ml = 0, 1, . . ., l
m s =
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a. I and III c. I, II, and IV b. II, III, and IV d. II and III 22. Which statement is false? a. The fifth fifth shell shell (or (or major major energy energy level) level) has one set of f f orbitals. b. A set of p p orbitals can accommodate a maximum of 6 electrons. c. There are 10 d orbitals in a set. d. None of the p orbitals are spherically symmetric. 23. Identify the following orbital.
a. d xy b.
c. f z d.
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24. An element with the outermost electron configuration ns2np3 would be in Group a. IIIA c. VIIA b. VA d. IIA
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25. a. b. 26. a. b.
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52 35 2 3
) have? How many neutrons does an atom of chlorine-35 ( c. 17 d. 18 How many atomic orbitals are there in the 4d subshell? c. 4 d. 5
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27. Choose th the re response th that in inclu cludes al all of of th the li listed elemen ments th that are d -transition -transition elements, and no others. I. Ti II. Mo III. Tl IV. Kr V. U a.
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IIV V and V c. IIIII and IV b. I and II d. II II and III 28. Which of the following statements is false? a. Transition Transition element elementss have larger larger atomic atomic radii than than the preceding preceding IA and and IIA elements elements in the the same period because transition elements have electrons in their d orbitals. b. Electrons Electrons in inner inner shells shells screen, screen, or shield, shield, electrons electrons in outer outer shells shells from the full full effect effect of the nuclear charge. c. The atomic atomic radii radii of represent representative ative elemen elements ts decrease decrease from from left to right right across across a period period (horizontal row in the periodic table). d. Within Within a family (vertic (vertical al group in in the periodic periodic table) table) of represent representative ative elements elements atomi atomicc radii increase from top to bottom. 29. Which ion or atom has the largest radius? a. c. Sr Rb b. d. Br Se 30. Oxygen wa was di discovered by Pr Priestley in in 17 1774 when he he ob observed th the __ ____. a. therma thermall decompo decomposit sition ion of of mercury mercury(II (II)) oxide, oxide, HgO b. b. elec electro troly lysi siss of of wat water er c. result resultss of fract fraction ional al disti distilla llatio tion n of air air d. 31. a. b. b. c. d. 32. a.
the thermal decomposition of potassium chlorate, KClO What do elements in the same vertical column of the periodic table have in common? the the same same phys physic ical al pro prope pert rtie iess simi simila larr chemic chemical al prop proper erti ties es the same same elec electro tron n config configura uratio tion n the same same numbe numberr of filled filled elec electro tron n energy energy leve levels ls Which Lewis Dot Formula is incorrect? c.
b.
d.
33. 33. Whic Which h Lewi Lewiss dot dot not notat atio ion n for for atom atomss and and ions ions is corr correc ectt for for the the rea react ctio ion n for for the the for forma mati tion on of calc calciu ium m phosphide? a.
b.
c.
d.
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34. a. b. c. d.
Which of th the fo following statements is is the be best de definition of of valence electrons? The The elec electr tron onss that that are are pai paired red.. The electr electrons ons that that are are unpai unpaired red.. The electr electrons ons in the p orbi orbital talss The electro electrons ns occupyi occupying ng the highest highest energy energy (outermo (outermost) st) level. level.
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35. 35. a.
What hat is the the form formu ula for the bin binary ary ion ionic compou mpound nd of lith ithium ium and and nit nitroge rogen? n? c.
LiN b. LiN ___ ____ _
Li N d.
Li N A che chemi mica call bon bond d for forme med d by by two two atom atomss sha shari ring ng one one or or mor moree pai pairs rs of elec electr tron onss is is cal calle led d a (or (or an) an) ____ ____
36. 36. bond. a. coordinate covalent b. ionic
c. nonpolar d. covalent
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37. 37. The The int inter ernu nucl clea earr dis dista tanc ncee at at whi which ch the the att attra ract ctiv ivee and and repu repuls lsiv ivee for force cess bal balan ance ce in a cov coval alen entt bon bond d is is called the ____. a. bond length d. single bond b. bond energy e. none of these c. stab stabil iliz izat atio ion n lengt length h
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38. The total numbe mber of vale alence electron rons that must be shown in the dot formu rmula for the C H Cl FO molecule is ____. (It is not necessary to draw the dot formula.) a. 50 c. 48 b. 42 d. 46
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39.
When writing the re relationship amon mong N, A, A, and S for H CO , N = ____, A = ____, an and S = ____. N
a.
A
40
S
16 b. 34
14 22
N c. 12
A
36
S
24 d. 34
12 24
10
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40. Draw th the do dot fo formul mula fo for ac acetylene, C H . Th The tw two ca carbo rbon at atoms ar are bo bonded to together an and eac each h carbon is bonded to one hydrogen. Each carbon-hydrogen bond is a ____ bond and each carbon-carbon bond is a ____ bond. a. single, triple c. double, double b. single, double d. double, single
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41. How many lone pairs of electrons electrons are there there on the Xe Xe atom in the XeF molecule? molecule? a. four c. three b. ze r o d. two
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42. a. 3 b. 2
How many resonance structures does the nitrate ion, NO -, have? c. 0 d. 1
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43. a. 2 b. 3
How many resonance struc ructures does the bicarbonate ate ion, HCO -, have? c. 1 d. 4
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44. a. b. 45. a. b. 46. a. b.
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How many resonance structures does O have? 4 c. 0 1 d. 2 Which molecule has the most polar covalent bond? HCl c. N2 IB r d. PH3 Which of the following statements concerning polar molecules is false? There must must be an odd odd number number of polar polar bonds bonds so that their polari polarities ties not not cancel. cancel. A molecule molecule with symmetri symmetrically cally arrange arranged d polar bonds bonds can be be polar if the central central atom atom is bonded to atoms of different elements. c. If there there are more than than one polar polar bond, bond, they must must not not be symmetrica symmetrically lly arranged arranged so so that their polarities cancel. d. There must must be at least least one polar polar bond bond or one one unshared unshared pair pair of electrons electrons on on the central central
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atom. 47. 47. The The hyb hybri ridi diza zati tion on asso associ ciat ated ed with with the the cen centr tral al atom atom of a mol molec ecul ulee in in whi which ch all all the the bon bond d ang angle less are are 109.5° is ____. a. sp3d c. sp3d 2 b. sp d. sp3 48. The bond angles associated with sp3d 2 hybridization are ____. a. 109° c. 90° and 180° b. 90° and 120° d. 120° 49. Which of th the fo following statements ab about polar mo molecules is is false? o a. A mol molec ecul ulee wit with h 180 180 bond angles can be polar. b. b. A mol molec ecul ulee wit with h 120 120 o bond angles can be polar. c. A molecu molecule le with with pola polarr bonds bonds can can be nonp nonpola olar. r. d. A molecul moleculee with with only only nonpo nonpolar lar bonds bonds can be polar. polar. 50. Molecules such as NF 3 are best described by assuming what kind of hybridization at the central atom? 3 a. sp d c. sp 3 2 b. sp d d. sp3 51. Which of of th the fo following sp species ha has sq square pl planar mo molecular ge geomet metry? 2a . SF 4 c. SO4 b. XeF4 d. CH4
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52. Which of the following statemen ments about mul multiple bonds is true? a. A sigma sigma bond bond resul results ts from from the the side-o side-on n overl overlap ap of p p atomic orbitals. 3 b. sp hybridization in carbon is associated with one double bond and two single bonds. c. A doubl doublee bond bond cons consist istss of two two sig sigma ma bonds bonds.. d. sp2 hybridization in carbon is associated with one double bond and two single bonds.
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53. a.
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How many sigma ( ) bonds and how many pi ( ) bonds does the ace acetylene ene molecule contain? c. 3 and 1 5 and 1 b. d. 3 and 2 2 and 2 54. 54. Whic Which h resp respon onse se incl includ udes es all all of the the mole molecu cule less list listed ed that that have have the the same same mole molecu cula larr geom geomet etry ry as electronic geometry, and only those molecules? BCl3, AsF5, NF3, H2S
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a.
c.
b.
d.
55.
Which, if any, of the compounds listed are not sp3d hybridized at the central atom?
I. II. III. IV. V.
BF 3 AsI5 SF 4 BrF5 XeF4
a. II III and IV c. al a ll are sp3d hybridized b. III and V d. I, IV, and V 56. What is the molecular geometry of the species, ICl2+. a. linear c. tetrahedral b. angular d. trigonal planar 57. Which of th the fo following can be be a Brønsted-Lowry ac acid? a. H2O c. CH4 b. H 2 d. NaOH 58. 58. What hat is is the the fo formu rmula and and mo molar larity ity of the sal salt pro produ duce ced d by by th the rea react ctio ion n of of 17 17 mL mL of of 0.3 0.33 3 M H2SO4 and 44 mL of 0.23 M Sr(OH)2? a. SrH2, 0.0920 M c. SrSO4, 0.0920 M b. SrSO4, 9.2 × 10-5 M d. Sr(OH)2, 0.165 M 59. A sample of im impure ir iron reacts wi with exactly 28.3 mL mL of 0.100 M HCl. How many grams of iron were contained in the sample? FeS (s) + 2HCl (aq) H2S (g) + FeCl2 (aq) a. 0.158 g c. 0.316 g b. 79.0 g d. 0.079 g 60. 60. Bala Balan nce this this equat quatiion for for a reac reacttion ion in in bas basic ic solut olutio ion. n. What hat is is the the coef coeffficie icien nt of of H 2O?
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KOH + Cl2 KClO3 + KCl + H2O a. 3 c. 2 b. 6 d. 4 61. In acidic solution MnO 4 oxidizes H 3AsO3, a weak acid, to H 3AsO4, a weak acid, and is reduced to 2+ Mn . Write the balanced net ionic equation for this reaction. How many H + are there in the balanced equation? a. 4 c. 2 b. 6 d. 1 62. Write the balanced net ionic equation for the reaction of hydrogen sulfide with bromate ions, BrO 3-, in acidic solution to form sulfur and bromide ions. How many H + are there in the balanced equation? a . ze r o c. 3 b. 2 d. 6 63. What volume of 0.0100 M KMnO4 solution is required to oxidize 42.5 mL of 0.0100 M FeSO4 sulfuric acid solution? MnO4- + 8H+ + 5Fe2+ Mn2+ + 5Fe3+ + 4H2O a. 8.5 mL c. 16.0 mL b. 31.9 mL d. 80.0 mL 64. What volume of 0.1066 M Na2S2O3 solution would be required to react with 24.32 mL of 0.1008 M I2 solution? Na2S2O3 + I2 a. 5.75 mL b. 34 34.50 mL
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65. 65.
Na2S4O6 + NaI (unbalanced) c. 11 11.50 mL d. 45 45.99 mL
When hen ho househ usehol old d amm ammon onia ia is mix mixed with bleac leach h, NaO NaOC Cl, tox toxic chl chlorin orinee ga gas an and hyd hydra razzine, ine, N 2H4 is
produced. What volume of 0.75 M NH3 would react with 100 mL of 0.35 M NaOCl? NH3 + OClCl2 + N2H4 (unbalanced) a. 23.5 Ml c. 100 mL b. 26 mL d. 47 mL 66. A 50.0-mL sample of K 2 Cr 2O7 solution oxidizes 1.500 g of Na2SO3 to Na 2SO4. Cr 2(SO4)3 is also produced. What is the molarity of the K 2Cr 2O7 solution? a. 2.96 M c. 0.0158 M b. 0.0952 M d. 0.0794 M 67. If 30.0 mL of 0.250 M HCl solution and 30.0 mL of 0.250 M NaOH are mixed, what is the molarity of the salt in the resulting solution? Assume that the volumes are additive. a. 0.0075 M c. 0.125 M b. 0.0625 M d. 0.250 M 68. What volume of 0.230 M potassium hydroxide solution, KOH, would completely neutralize 27.4 mL of 0.205 M sulfurous acid solution, H2SO3? a. 61.5 mL c. 24.4 mL b. 12.2 mL d. 48.8 mL 69. 69. A sam sampl plee of of hel heliu ium m occ occup upie iess 1.4 1.40 0 L at stan standa dard rd cond condit itio ions ns.. Wha Whatt pres pressu sure re will will it exer exertt in in a 0.5 0.500 00 L vessel at 100.°C? a. 1.56 × 103 torr c. 371 torr b. 624 torr d. 2.91 × 103 torr 70. A sample of nitrous oxide, N 2O, occupies 1.65 L at STP. What is the mass of the sample? a. 18.9 g c. 22.1 g b. 28.6 g d. 32.4 g 71. A 7.9 7.97 7 g sample of of ga gas oc occupies 5. 5.25 L at ST STP. Wh What is is th the fo formula of of th the ga gas? a. CO2 c. PCl3 b. NO d. N2H4 72. What mass of methane, CH 4, is contained in a 500.-mL sample of CH 4 at STP? a. 0.407 g c. 0.357 g b. 0.212 g d. 0.390 g 73. Calculate the density of O 2, in g/L, at STP. a. 0.714 g/L c. 1.62 g/L b. 1. 1.43 g/L d. 1. 1.14 g/L 74. A 5.00 L container contains CH 4, H2, and Xe at 35°C with a total pressure of 1.81 atm. If there are equal moles of each gas, what is the partial pressure of H 2? a. 0.603 atm c. 0.034 atm b. 1. 1.81 atm d. 3. 3.05 atm 75. A mixture of gases containing 21.0 g of N 2, 106.5 g of Cl 2 and 12.0 g of He at 14°C is in a 50.0-L container. What is the total pressure in the vessel? a. 2.7 atm c. 2.5 atm
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b. 1.8 atm d. 2.2 atm 76. 76. Which hich of the the foll follo owin wing situ situat atio ions ns would ould one expe expect ct the the mos most rea reall gas gas beha behav vior? ior? a. He at 10°C c. NH3 at 5 atm b. CO2 at 100 atm d. CO at 25°C
77. 77. The van van der der Wa Waaals cons consta tan nt, b, in the the rela relattions ionshi hip p (P + )(V )(V - nb) = nRT nRT is a fact facto or that that corr correc ects ts for a. the attra attracti ctive ve forces forces betw between een gas gas molecu molecules les.. b. the volu volume me occup occupied ied by by the gas gas molec molecule ules. s. c. deviat deviation ionss in the gas const constant ant,, R. d. the avera average ge veloc velociti ities es of the the gas molec molecule ules. s. 78. 78. Calc Calcu ulate late the the pre press ssur uree (in (in atm) atm) exer exerte ted d by by 1.0 1.00 0 mo mole of acet acetyl ylen enee at at 125 125°C °C in a 20. 20.00-li lite terr con conta tain iner er.. The van der Waals constants for acetylene are: a = 20.0 L 2 • atm/mol2, b = 0.100 L/mol. a. 1.59 c. 1.64 b. 0.485 d. 0.533 79. Which liquid would evaporate most quickly at room tempe mperat rature? re? a. Ethy Ethyle lene ne glyc glycol ol,, HO-C HO-CH H 2-CH2-OH, 62 g/mol b. H2O, 18 g/mol c. Vege Vegeta tabl blee oil oil,, 895 895 g/mo g/moll d. Gasoline, C8H18, 114 g/mol 80. 80. Calc Calcu ulate late the the amou amount nt of heat heat (in (in jou joules) les) requ requir ired ed to conv conver ertt 92. 92.5 5 g of wate waterr at at 25. 25.0° 0°C C to to ste steam am at 108.0°C. (Sp. heat of H 2O( ) = 4.18 4.18 J/g•°C J/g•°C,, Sp. heat heat of H2O(g) = 2.03 J/g•°C, heat of vap. of H 2O( ) = 2.260 .260 kJ/g) a. 6.43 × 105 J c. 3.05 × 104 J b. 2.26 × 105 J d. 2.40 × 105 J
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81. a. b. c. d. 82. a. b. c.
Which one of the following statements is not applicable to ionic solids? Ionic Ionic solid solidss have have fairly fairly high high melt melting ing poin points. ts. Most Most ionic ionic solid solidss are hard hard and and britt brittle. le. Ionic solids solids are usuall usually y excellent excellent conductors conductors of electric electric curren current. t. The units units that occupy occupy the the lattice lattice points points are are ions. ions. Which statement is false? About About 26% of the the total volume volume of any cubic cubic close close packed packed crystal crystal lattic latticee is empty empty space. space. Two solids solids that crysta crystalliz llizee in the same kind kind of crystal crystal lattice lattice are said to to be isomorphou isomorphous. s. The size size of an ion ion in a crystal crystal is influen influenced ced by its its environmen environment, t, that is, is, by the the other ions ions surrounding it. d. An examp example le of an an amorph amorphous ous solid solid is diam diamond ond.. 83. Which one of the following substances is incorrectly matched with the kind of solid it forms? Substance a.
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Kind of Solid
sulfur dioxide molecular c. methane molecular b. lithium ionic d. calcium bromide ionic 84. 84. If the the mol molee fra fract ctio ion n of of met methy hyll alc alcoh ohol ol in a sol solut utio ion n (wi (with th only only wate water) r) is 0.28 0.28,, wha whatt is is the the mole mole frac fracti tion on of the water? a. 0.62 c. 0.72 b. 0.28 d. 1.28 85. 85. Calc Calcu ulate late the the boi boilling ing po point int of of a so solut lution ion pre prep pared ared by dis disso solv lvin ing g 70. 70.0 0 g of of nap naph hthal thalen ene, e, C 10H8 (a nonvolatile nonelectrolyte), nonelectrolyte), in 220.0 g of benzene, C 6H6. The K b for benzene = 2.53°C/ m. The boiling point of pure benzene is 80.1°C. a. 73.8°C c. 106.3°C b. 87.8°C d. 86.4°C 86. 86. Calc Calcu ulate late the the free freezi zing ng poin pointt of a solu soluti tio on that hat con contain tainss 8.0 g of sucro crose (C 12H22O11) in 100. g of H 2O. for H O = 1.86°C/ K f f m. 2 a. - 0.044°C c. 0.04°C b. - 0.44°C d. - 0.22°C 87. 87. Calc Calcu ulate late the the fre freez ezin ing g poi point nt of a sol solut utio ion n tha thatt con conta tain inss 68. 68.4 4 g of sucr sucros osee (ta (tabl blee sug sugar ar)) in in 300 300.. g of water. One mole of sucrose is 342 g. K f f for H2O = 1.86°C/m. a. -0.372°C c. -1.24°C b. -0.186°C d. -0 - 0.558°C 88. 88. When When 35.0 35.0 g of of an an unk unkno nown wn none nonele lect ctro roly lyte te is diss dissol olve ved d in in 220 220.0 .0 g of of ben benze zen ne, the the sol solut utio ion n boil boilss at at 83.2°C. Calculate the molecular weight of the unknown nonelectrolyte. The K b for benzene = 2.53°C/ m. The boiling point of pure benzene is 80.1°C. a. 156 g/mol c. 20.3 g/mol b. 183 g/mol d. 130 g/mol
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89. How mu much he heat is re released or or ab absorbed in in th the re reacti ction of of 10 10.0 grams of Si SiO 2 (quartz) with excess hydrofluoric acid? SiO2(s)
+
4HF(aq)
SiF4(g)
-320.8
-1615
-910.9
+ 2H2O( ) -285.8
∆ H
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a. 1.25 kJ released c. 6.56 kJ released b. 11.3 kJ released d. 1.25 kJ absorbed 90. Which statement is false? a. ∆ H is equal to ∆ E for the process: 2H 2(g) + O2(g) 2H2O(g). b. No work work is done done in a reaction reaction occurri occurring ng in a bomb calor calorimeter imeter.. c. ∆ H is often nearly equal to ∆ E . d. The thermod thermodynami ynamicc quantity quantity most most easily easily measured measured in a "coffee "coffee cup" cup" calorimeter calorimeter is is ∆ H . 91. The reaction of 1.00 mole of H 2(g) with 0.500 mole of O 2(g) to produce 1.00 mole of steam, H 2O(g), at 100°C and 1.00 atm pressure evolves 242 kJ of heat. Calculate ∆ E per mole of H 2O(g) produced. The universal gas constant is 8.314 J/mol•K. a. +240 kJ c. +242 kJ b. -242 kJ d. -240 kJ 0 92. Calculate ∆ S for the reaction below at 25°C. S 0 for SiH4 = 204.5 J/mol•K, for O 2(g) = 205.0 J/mol•K, for SiO2(s) = 41.84 J/mol•K, for H 2O( ) = 69.9 69.91 1 J/mo J/mol•K l•K.. SiH4(g) + 2O2(g) a. -677.0 J/K b. -880.3 J/K
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93.
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____
-353.5 J/K d. -432.8 J/K
A2 + 2B2
What would the concentration of AB 2 be after 60 minutes m inutes if the initial concentration was 1.45 mol/L? -5 a. 2.0 × 10 M c. 4.9 × 10-5 M b. 1.9 × 10-4 M d. 2.4 × 10-5 M 94. 94. What What woul would d be be the the acti activa vati tion on ener energy gy of a rea react ctio ion n if if its its rate rate cons consta tant nt at 35°C 35°C was was dou doubl blee the the valu valuee of of its rate constant at 25°C? a. 8.12 kJ/mol c. 52.9 kJ/mol b. 68.3 J/mol d. 63.8 kJ/mol 95. A catalyst a. increases ∆ H for the process. b. increases increases the rate rate at which which equilibriu equilibrium m is reached withou withoutt changing changing the equilib equilibrium rium constant. c. increases increases the amount amount of products products present present at at equilib equilibrium. rium. d. lowers ∆ S for the process. 96. Consider the gas phase system below at a high temperature. The form of the expression for the equilibrium constant, K c, ____. 4NH3 + 5O2 a.
4NO + 6H2O c.
is K c = b.
___ ____ _
c.
At 100 K the reaction below obeys the rate law rate = k [AB [AB2]2 where k = 5.7 M -1•s-1. 2AB2
___ ____ _
SiO2(s) + 2H2O( )
is K c = d. cannot cannot be dete determi rmined ned with without out rate rate data data
is K c = 97. 97. What hat is the the equ equilib ilibri riu um con constan tant exp express ressio ion n for for the follo ollow wing ing reac reacttion? ion? C3H8(g) + 5 O 2(g) a.
3 CO2(g) + 4 H 2O( ) c.
b.
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____
d.
K c for the reaction 2A(g) + 3B(g) 98. What is the value of K 0.60 M , [B] = 0.30 M , [C] = 0.10 M and [D] = 0.50 M ? a. 2.4 c. 0.088 b. 0.15 d. 0.51 99. The K c for the following reaction is 56.2 at 305°C. A2(g) + B2(g)
____
2C(g) + D(g) if at equilibrium [A] =
2 C(g)
If a reaction is initiated with 2.4 M of each substance, what is the equilibrium concentration of C? a. 4.3 M c. 5.7 M b. 1.2 M d. 2.4 M 100. Consider th the re reversi rsible re reaction at eq equilibrium at at 39 392°C. 2A(g) + B(g)
C(g)
The partial pressures are found to be: A: 6.70 atm, B: 10.1 atm, C: 3.60 atm. What is the concentration of B at equilibrium? a. 0.200 M c. 1.64 M b. 0.185 M d. 1.13 M
