Solution Preparation Final Goueth - MiraCosta College



SOLUTION

Final Exam Preparation problems for Chemistry 11

1. A dilute HCl solution is to be prepared from a more concentrated solution. Which of pieces of glassware will give the highest level of precision?

(A) graduated cylinder and volumetric flask (B) two graduated cylinders

(C) pipette and graduated cylinder (D) pipette and volumetric flask

2. An alloy of gold and silver contains 38.5% silver by mass and has a density of 14.6 g mL¯1. What is the molar concentration of silver in this alloy?

(A) 52.1 mol L¯1 (B) 45.6 mol L¯1 (C) 3.57 mol L¯1 (D) 2.64 mol L¯1

3. As2S3 reacts with O2 to give SO2 and As2O3. What is the smallest whole number coefficient for O2 when the equation for this reaction is balanced correctly?

_As2S3(s) + _O2(g) ---> _As2O3(s) + _SO2(g)

(A) 3 (B) 5 (C) 7 (D) 9

4. A 0.242 g sample of potassium is heated in oxygen. The result is 0.440 g of a crystalline compound. What is the formula of this compound?

(A) KO (B) K2O (C) KO2 (D) KO3

5. What volume of 3.0 M Na2SO4 must be added to 25 mL of 1.0 M BaCl2 to produce 5.0 g of BaSO4?

(A) 7.2 mL (B) 8.3 mL (C) 10.0 mL (D) 14 mL

6. These three equations describe an oxidation-reduction method for determining dissolved oxygen in water. How many moles of S2O32¯ are equivalent of each mole of O2?

1) 2Mn2+(aq) + 4OH¯(aq) + O2(g) ---> 2MnO2(s) + 2H2O(l)

2) MnO2(s) + 2I¯(aq) + 4H+(aq) ---> Mn2+(aq) + I2(aq) + 2H2O(l)

3) 2S2O32¯(aq) + I2(aq) ---> S4O62¯(aq) + 2I¯(aq)

(A) 0.5 (B) 1 (C) 2 (D) 4

7. A 15 mL sample of 0.20 M MgCl2 is added to 45 mL of 0.40 M AlCl3. What is the molarity of Cl¯ ions in the final solution?

(A) 1.0 M (B) 0.60 M (C) 0.35 (D) 0.30 M

8. How many electrons are present in 2.0 x 10¯3 moles of 188O2¯?

(A) 1.2 x 1021 (B) 9.6 x 1021 (C) 1.2 x 1022 (D) 1.9 x 1022

9. In which change of state are covalent bonds broken?

(A) evaporation of water (B) fusion of sodium chloride

(C) vaporization of diamond (D) sublimation of dry ice

10. By what factor does the average velocity of a gaseous molecule increase when the absolute temperature is doubled?

(A) 1.4 B) 2.0 (C) 2.8 (D) 4.0

11. Which species is expected to have the highest boiling point at 1 am pressure?

(A) O2 (B) CO (C) CO2 (D) HCHO

12. Calculate ΔH° for this reaction.

C2H2(g) + 2H2(g) ---> C2H6(g)

|ΔΗCombustion, kJ mol¯1 |

|C2H2(g) |-1300 |

|H2(g) |-286 |

|C2H6(g) |-1560 |

(A) -312 kJ (B) -26 kJ (C) +26 kJ (D) +312 kJ

13. Which statement about work and heat is true?

A) A given quantity of heat can be completely converted to work.

(B) Heat and work are both state functions.

(C) Some heat is always produced when work is done.

14. How many moles of elections are transferred when this equation is balanced with the smallest whole number coefficients?

_IO3¯ + _H2O2 + _H+ ---> _I2 + _O2 + _H2O

(A) 2 (B) 4 (C) 5 (D) 10

15. The visible spectrum of the hydrogen atom consists of a series of lines that

A. converge at low energies. B. converge at high energies.

C. are separated by equal energies. D. are randomly spaced.

16. When the elements C, N and Si are arranged in order of increasing first ionization energy, which is the correct order?

A. C < N < Si B. N < C < Si C. Si < C < N D. Si < N < C

17. Which is a possible set of quantum numbers for a valence electron in ground state atom of phosphorus?

|  |n |l |ml |ms |

|A. |2 |1 |0 |+1/2 |

|B. |3 |0 |0 |0 |

|C. |3 |1 |-1 |+1/2 |

|D. |3 |2 |1 |-1/2 |

18. These are the first eight ionization energies for a particular neutral atom. All values are expressed in MJ mol¯1. How many valence electrons does this atom possess?

|1st|2nd |3rd |4th |

|A. |2 |2 |2 |

|B. |3 |2 |0 |

|C. |3 |1 |2 |

|D. |3 |0 |4 |

22. In the Lewis structure for the BrF4¯ ion, how many lone pairs of electrons are placed around the central atom?

(A) 0 (B) 1 (C) 2 (D) 3

23. What term is used for the measure of an atom's attraction for the electrons that constitute a covalent bond?

(A) ionization energy (B) bond energy (C) electron affinity (D) electronegativity

24. One way of writing the Lewis structure of the cyanate ion, OCN¯, places one double bond between the carbon atom and the oxygen atom and another double bond between the carbon atom and the nitrogen atom. What are the formal charges on the oxygen, carbon, and nitrogen atoms, respectively for this structure?

(A) 0, 0, -1 (B) -1, 0, 0 (C) -1, +1, -1 (C) -2, 1, 0

25. All of these species have the same number of valence electrons as NO3¯ except

(A) CO32¯ (B) HCO3¯ (C) NF3 (D) SO3

26. Which set contains no ionic species?

(A) NH4Cl, OF2, H2S (B) CO2, Cl2, CCl4 (C) BF3, AlF3, TlF3 (D) I2, CaO, CH3Cl

27. Which element exhibits both +1 and +3 oxidation numbers in its compounds?

(A) B (B) Be (C) Sn (D) Ti

28. Which are nonpolar molecules?

1. NCl3 2. SO3 3. PCl5

(A) 1 only (B) 2 only (C) 1 and 3 only (D) 2 and 3 only

29. When FeCl3 is ignited in an atmosphere of pure oxygen, this reaction takes place.

4 FeCl3(s) + 3 O2 (g) ---> 2 Fe2O3(s) + 6 Cl2 (g)

If 3.0 mol of FeCl3 are ignited in the presence of 2.0 mol of O2 gas, how much of which reagent is present in excess and therefore remains unreacted?

(A) 0.33 mol FeCl3 remain unreacted (B) 0.67 mol FeCl3 remain unreacted

(C) 0.25 mol O2 remain unreacted (D) 0.50 mol O2 remain unreacted

30. How many grams of SbF3 are needed to produce a gram of Freon-12, CCl2F2, according to the reaction represented by this equation?

3 CCl4 + 2 SbF3 ---> 3 CCl2F2+ 2 SbCl3

|Substance |Molar Mass |

|SbF3 |179 g mol¯1 |

|CCl2F2 |121 g mol¯1 |

(A) 0.667g (B) 0.986g (C) 1.50g (D) 2.22g

31. A self-contained breathing apparatus uses potassium superoxide, KO2, to convert the carbon dioxide and water in exhaled air into oxygen, as shown by the equation.

4 KO2(s) + 2 H2O (g) + 4 CO2(s) ---> 4 KHCO3(s) + 3 O2 (g)

How many molecules of oxygen gas will be produced from the 0.0468 g of carbon dioxide that is exhaled in a typical breath?

(A) 4.8 x 1020 (B) 6.4 x 1020 (C) 8.5 x 1020 (D) 1.9 x 1021

32. A student finds that 31.26 mL of a 0.165 M solution of barium hydroxide, Ba (OH)2, solution is required to just neutralize 25.00 mL of a citric acid, H3C6H5O7, solution. What is the concentration of the H3C6H5O7 solution?

(A) 0.413 M (B) 0.309 M (C) 0.206 M (D) 0.138 M

33. Which Group III element is expected to have physical and chemical properties that are the least similar to the other elements in that family?

(A) B (B) Al (C) Ga (D) Tl

34. A pure gas that is 14.4% hydrogen and 85.6% carbon by mass has a density of 2.5 g L¯1 at 0 °C and 1 atm pressure. What is the molecular formula of the gas?

(A) CH2 (B) C2H4 (C) C4H8 (D) C6H12

35. Sodium chloride, NaCl, usually crystallizes in a face-centered cubic lattice. How many Cl¯ ions are in contact with any single Na+ ion?

(A) 4 (B) 6 (C) 8 (D) 12

36. Use the bond energies in the table to determine ΔH for the formation of hydrazine, N2H4, from nitrogen and hydrogen according to this equation:

N2(g) + 2 H2(g) ---> N2H4(g)

|Bond Energies |

|N-N |159 kJ mol¯1 |

|N=N |418 kJ mol¯1 |

|N {triple bond} N |941 kJ mol¯1 |

|H-H |436 kJ mol¯1 |

|H-N |389 kJ mol¯1 |

(A) ΔH = 711 kJ (B) ΔH = - 98 kJ (C) ΔH = + 98 kJ (D) ΔH = + 711 kJ

37. Use the given heats of formation to calculate the enthalpy change for this reaction:

B2O3(s) + 3 COCl2(g) ---> 2 BCl3(g) + 3 CO2(g)

|Enthalpy of Formation Data, kJ mol¯1 |

|B2O3(s) |- 1272.8 |

|COCl2(g) |- 218.8 |

|BCl3(g) |- 403.8 |

|CO2(g) |- 393.5 |

(A) 694.3 kJ (B) 354.9 kJ (C) -58.9 kJ (D) -3917.3 kJ

38. What is the change in internal energy, ΔE, for a system that does 70 joules of work as it absorbs 45 joules of heat?

(A) 115 J (B) 25 J (C) -25 J (D) -115 J

39. When this oxidation-reduction equation is correctly balanced, what is the mole ratio of reducing agent to oxidizing agent?

MnO4¯ + Sn2+ + H+ ---> Mn2+ + Sn4+ + H2O

(A) 1:1 (B) 2:1 (C) 4:1 (D) 5:2

40. The hydrogen line spectrum provides evidence for the

(A) Heisenberg Uncertainly Principle (B) wavelike properties of light

(C) diatomic nature of H2 (D) quantized nature of atomic energy states

41. What is the number of unpaired electrons in a manganese atom (Z = 25) in its lowest energy states?

(A) 1 (B) 3 (C) 5 (D) 7

42. Ions with the electronic structure 1s2 2s2 2p6 3s2 3p6 would not be present in which aqueous solution?

(A) NaF(aq) (B) NaCl(aq) (C) KBr(aq) (D) CaI2(aq)

43. An element with the electron configuration [Xe]4f14 5d7 6s2, is

(A) an alkaline earth element (B) a transition element (C) an inert gas (D) a rare earth

44. The bonds in ozone, O3, are best represented as

(A) two double bonds (B) a single and a double bond that switch positions rapidly

(C) distinct single and double bonds (D) something between a single and a double bond

45. Which pair of substances will have the most similar geometry?

(A) SO3 and SO32¯ (B) SO3 and CO32¯ (C) SO3 and SO42¯ (D) SO42¯ and CO32¯

46. What hybridization is expected for ClF3?

(A) sp3 (B) dsp2 (C) dsp3 (D) d2sp3

47. Which bond properties are consistent with one another?

|  |Bond Order |Bond Length | |

|(A) |higher |shorter | |

|(B) |higher |longer | |

|(C) |lower |shorter | |

| | | | |

48. Which hydrogen halide would you expect to have the lowest boiling point?

(A) HF (B) HCl (C) HBr (D) HI

49. Which substance has a dipole moment?

(A) CCl4 (B) CH2Cl2 (C) C2Cl2 (D) C2Cl4

50. When the isoelectronic species, K+, Ca2+, and Cl¯, are arranged in order of increasing radius, what is the correct order?

(A) K+, Ca2+, Cl¯ (B) K+, Cl¯, Ca2+ (C) Cl¯, Ca2+, K+ (D) Ca2+, K+, Cl¯

51. Which Group 2 element has chemical properties least like the other members of the group?

(A) Be (B) Ca (C) Sr (D) Ba

52. In the vapor state which atom has the largest ionization energy?

(A) Na (B) K (C) Mg (D) Ca

53. When equal volumes of 1 M Na2SO4 and 1 M solutions of two different ions are mixed, a precipitate forms with one of the ions but not with the other. The two ions could be

(A) Ba2+ and Mg2+ (B) Al3+ and Zn2+ (C) Cu2+ and K+ (D) Pb2+ and Ba2+

54. The geometry of the atoms in the species PCl4+ is best described as

(A) tetrahedral (B) see-saw (C) square planar (D) trigonal bipyramidal

55. When 4.50 g of Fe2O3 is reduced with excess H2 in a furnace, 2.60 g of metallic iron is recovered. What is the percent yield? The Molar Mass of Fe2O3 is 159.7 g mol¯1

Fe2O3 + 3 H2 ---> 2 Fe + 3 H2O

(A) 82.6 (B) 70.0 (C) 57.8 (D) 31.5

56. Which of these compounds contains the greatest percentage of nitrogen?

(A) C6H3N3O7 (B) CH4N2O (C) LiNH2 (D) Pb(N3)2

57. Analysis shows a certain compound to be 37.51% C, 4.17% H, and 58.32% O. What is its empirical formula?

(A) C3H4O4 (B) C4H5O5 (C) C5H7O6 (D) C6H8O7

58. A sample of a compound of xenon and fluorine contains molecules of a single type; XeFn, where n is a whole number. If 9.03 x 1020 of these XeFn molecules have a mass of 0.311 g, what is the value of n?

(A) 2 (B) 3 (C) 4 (D) 6

59. The combustion reaction of C3H8O in O2 is represented by this equation.

2 C3H8O + 9 O2 ---> 6 CO2 + 8 H2O

When 3.00 g C3H8O and 7.38 g O2 are combined, how many moles of which reagent remain?

(A) 0.0056 mol O2 (B) 0.024 mol C3H8O (C) 0.24 mol O2 (D) 0.18 mol C3H8O

60. Formaldehyde is oxidized by dichromate ions in acid solution to give formic acid as represented by this equation.

3 HCOH + Cr2O72¯ + 8 H+ ---> 3 HCOOH + 2 Cr3+ + 4 H2O

If 15.62 mL of 0.125 M K2Cr2O7 exactly react with 25.00 mL of formaldehyde solution, what is the molarity of the formaldehyde?

(A) 0.00585 M (B) 0.0260 M (C) 0.0781 M (D) 0.234 M

61. If 0.25 mol of a gas has a mass of 4.0 g and occupies a volume of 5.6 L at standard temperature and pressure, what would be the mass and volume of 0.50 mol of this gas at standard temperature and 2.0 atm pressure?

(A) 4.0 g and 5.6 L (B) 4.0 g and 11 L (C) 8.0 g and 5.6 L (D) 8.0 g and 11 L

62. If 34.0 mL of O2 are collected over H2O at 740 mmHg and 25 °C, what will be the volume of dry O2 at 0 °C and 760 mmHg? Vapor Pressure at 25 °C of H2O is 23.8 mmHg

(A) 29.4 mL (B) 30.3 mL (C) 32.0 mL (D) 33.1 mL

63. What is the molar mass of an ideal gas if a 0.622 g sample of this gas occupies a volume of 300. mL at 35 °C and 789 mmHg?

(A) 44.8 g mol¯1 (B) 48.9 g mol¯1 (C) 50.5 g mol¯1 (D) 54.4 g mol¯1

64. Which is true about equal volumes of CH4 and O2 at 20 °C and 1 atm pressure?

(A) The CH4 sample has a mass that is one-half that of the O2 sample.

(B) The number of O2 molecules is twice as large as the number of CH4 molecules.

(C) The average kinetic energy of the O2 molecules is one-half that of the CH4 molecules.

(D) The average velocity of the O2 molecules is one-half that of the CH4 molecules.

65. 168.00 J of energy are added to a sample of gallium initially at 25.0 °C, the temperature rises to 38.0 °C. What is the volume of the sample?

|Data for Gallium, Ga |

|specific heat |0.372 J g¯1 °C¯1 |

|density |5.904 g cm¯3 |

(A) 2.38 cm3 (B) 4.28 cm3 (C) 5.88 cm3 (D) 31.0 cm3

66. The combustion of ammonia is represented by this equation.

4 NH3(g) + 5 O2(g) ---> 4 NO(g) + 6 H2O (g) ΔH=- 905 kJ

|Enthalpy of formation data |

|NO2(g) |90.4 kJ mol¯1 |

|H2O(g) |- 241 kJ mol¯1 |

What is the enthalpy of formation for NH3(g)?

(A) - 499 kJ mol¯1 (B) - 46.1 kJ mol¯1 (C) 184 kJ mol¯1 (D) -44.9 kJ mol¯1

67. Which electronic transition occurs with the greatest release of energy in a hydrogen atom?

(A) n = 2 --> n = 3 (B) n = 3 --> n = 9 (C) n = 9 --> n = 3 (D) n = 3 --> n = 2

68. For which element could the last electron have the quantum numbers n = 4, l = 2?

(A) Ca (Z = 20) (B) Ti (Z = 22) (C) Si (Z = 14) (D) Rh (Z = 45)

69. Which atom in its ground state contains the greatest number of unpaired electrons ?

(A) S (Z = 16) (B) P (Z = 15) (C) Si (Z = 14) (D) Al (Z = 13)

70. Which of these isoelectronic species will be the largest?

(A) S2¯ (B) Cl¯ (C) K+ (D) Ca2+

71. Which process will release the greatest quantity of energy?

(A) O(g) ---> O+(g) + e¯ (B) O+(g) ---> O2+(g) + e¯

(C) O¯(g) + e¯ ---> O2¯(g) (D) O(g) + e¯ ---> O¯(g)

72. What are the hybridizations of carbon 1 and carbon 2 in the hydrocarbon? (Carbon 1 is the carbon farthest to the left and carbon 2 is the one boldfaced, the middle of the three carbons.)

CH3CH=CH2

(A) sp3, sp (B) sp3, sp2 (C) sp2, sp2 (D) sp, sp2

73. According to valence bond theory, what hybrid orbital are used by the central atom in SF4?

(A) sp3 (B) dsp2 (C) dsp3 (D) d2sp3

74. What is the maximum number of covalent bonds that can be formed by an element with the outer electron configuration of 3s2 3p4?

(A) 2 (B) 3 (C) 4 (D) 6

75. In which pair of species do the central atoms have the same geometry?

(A) NH3, NO3¯ (B) BF3, NO3¯ C) BF3, ClF3 (D) NH3, ClF3

76. Use the given bond energies and this equation to calculate the H-F bond energy in kJ mol¯1

|Bond Energies, kJ mol¯1 |

|H2 |436 |

|F2 |135 |

H2(g) + F2(g) ---> 2 HF (g) ΔH = - 541 kJ

(A) 1130 (B) 556 (C) 48 (D) 24

77. Which element can exhibit more than one oxidation state in compounds?

1. Cr 2. Pb 3. Sr

(A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1,2 and 3

78. When these species are arranged in order of increasing bond energy, what is the correct sequence?

(A) N2, O2, F2 (B) F2, O2, N2 (C) O2, F2, N2 (D) O2, N2, F2

79. All of these sets of quantum numbers are permissible except

|  |n |l |ml |ms |

|(A) |1 |0 |0 |+1/2 |

|(B) |2 |2 |0 |-1/2 |

|(C) |3 |1 |1 |-1/2 |

|(D) |3 |2 |-1 |+1/2 |

80. A 20.00 mL sample of a Ba(OH)2 solution is titrated with 0.245 M HCl. If 27.15 mL of HCl is required, what is the molarity of the Ba(OH)2 solution?

(A) 0.166 M (B) 0.180 M (C) 0.333 M (D) 0.666 M

81. 0.250 g of an element, M, reacts with excess fluorine to produce 0.547 g of the hexafluoride, MF6. What is the element?

(A) Cr (B) Mo (C) S (D) Te

82. How many moles of Na+ ions are in 20 mL of 0.40 M Na3PO4?

(A) 0.0080 (B) 0.024 (C) 0.050 (D) 0.20

83. What is the mass percent of oxygen in Al2(SO4)3 . 18 H2O (The molar mass of this substance is 666.43 g / mol)?

(A) 9.60 (B) 28.8 (C) 43.2 (D) 72.0

84. What is the coefficient for H+(aq) when the equation is balanced with whole number coefficients?

_Mn2+(aq) + _BiO3¯(aq) + _H+(aq) _Bi3+(aq) + _MnO4¯(aq) + _H2O (l)

(A) 3 (B) 4 (C) 7 (D) 14

85. What is the number of O2 molecules in the 2.5 g of O2 inhaled by the average person in one minute?

(A) 1.9 x 1022 (B) 3.8 x 1022 (C) 4.7 x 1022 (D) 9.4 x 1022

86. The molar mass of a gas with a density of 5.8 g L¯1 at 25 °C and 740 mmHg is closest to

(A) 10 g mol¯1 (B) 20 g mol¯1 (C) 150 g mol¯1 (D) 190 g mol¯1

87. Which substance would be expected to exhibit the greatest surface tension at 25 °C?

(A) CH3OCH3 (B) C2H5OH (C) CH3CH(OH)CH3 (D) CH2(OH)CH2OH

88. What is the ΔH°f for N2O in kJ mol¯1 (heats of formation: NH3 = -45.9 kJ mol¯1 and H2O = -241.8 kJ mol¯1) ?

3 N2O(g) + 2 NH3(g) ---> 4 N2(g) + 3 H2O(g) ΔH = -879.6 kJ

(A) +246 (B) +82 (C) –82 (D) -246

89. What is the change in internal energy, ΔE, for a reaction that gives off 65 joules of heat and does 38 joules of work?

(A) -103 J (B) -27 J (C) +27J (D) +103 J

90. The value of ΔH for a reaction can be found by appropriate combination of bond enthalpies (the energy required to break a particular bond, represented BE). Which expression will give ΔH for this reaction?

C2H4(g) + H2(g) ---> C2H6(g)

(A) BEC=C +BEH-H - [BEC-C + 2BEC-H] (B) BEC-C + 2BEC-H - [BEC=C + BEH-H]

(C) (1/2)BEC=C + BEH-H - 2BEC-H (D) 2BEC-H - (1/2)BEC=C + BEH-H

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