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1. According to the Bronsted—Lowry definition, which chemical species can function both as an acid and as a base? a. Cl — b. SO 4 2— c. NH 4 + d. HCO 3 — e. H3O+ 2. In the reaction CN—^ + H 2 O !" HCN + OH— which is an acid—base conjugate pair? a. H2O and HCN b. H2O and OH— c. CN—^ and H 2 O d. HCN and OH— 3. Given that HX is a stronger Bronsted acid than HY in aqueous solution, which is true of a 1 M solution of NaX a. It is less basic than a 1 M solution of NaY. b. It is more basic than a 1 M solution of NaY. c. It yields a neutral solution. d. It is more concentrated than a 1 M solution of NaY. 4. The pH of a 0.03 M HCl solution is a. 1. b. 2. c. 3. d. 12. 5. The pH of a 1.0 x 10—3^ M Ba(OH) 2 solution at 25 oC is a. 2. b. 3. c. 11. d. 11. 6. Which is the strongest acid?
a. HClO b. HClO 2 c. HClO 3 d. HClO 4
7. Which salt reacts with water (hydrolyzes) to produce a basic solution?
a. NaC 2 H3O 2 b. NaNO 3 c. NH4Cl d. BaSO 4
8. The weakest of the bases listed is
Acid Conjugate Base
Ka (Ionization Constant of Acid) HCl Cl —^ 100% ionized HSO 4 —^ SO 4 2—^ 1.2 x 10- H2S HS—^ 5.7x10 - HS—^ S2—^ 1.2x10- a. Cl — b. CN— c. HS— d. S2— e. SO 4 2—
9. The oxide of which element will react with water to form the strongest acid?
Main Groups Period I II II I
IV V VI VII O
First Second X Y Z P Q S U Third W R T M
a. W b. M c. P d. R e. Z
10. Which statement is a logical inference from the fact that a 0.10 M solution of potassium acetate KC2H3O2, is less alkaline than a 0.10 M solution of potassium cyanide, KCN?
a. Hydrocyanic acid is a weaker acid than acetic acid. b. Hydrocyanic acid is less soluble in water than acetic acid. c. Cyanides are less soluble than acetates d. Acetic acid is a weaker acid than hydrocyanic acid
11. In the titration of 50.0 mL of 0.100 M benzoic acid (a monoprotic acid) with 50.0 mL of 0.100 M NaOH, the properties of the solution at the equivalence point will correspond exactly to the properties of a. a 0.100 M sodium solution. b. a 0.0500 M sodium hydroxide solution. c. a 0.0500 M benzoic acid solution. d. a 0.0500 M sodium benzoate solution.
12. A mixture of which pair of 0.1 M aqueous solutions would constitute a buffer? a. NaOH and NaCl b. HCl and NaOH c. HCl and NaCl d. NH 3 and NH4NO 3 13. What do these have in common? (^20) Ne 19 F1- (^24) Mg2+
a. the same number of protons b. the same number of neutrons c. the same number of electrons d. the same size
14. The number of neutrons in the nucleus of an atom of 1327 Al is a. 40 b. 13 c. 27 d. 14 e. 9 15. The orbitals of 2p electrons are often represented as being a. elliptical. b. Pyramidal c. Tetrahedral d. dumbbell shaped e. spherical. 16. The element in Period 5, Group 3A, has the outer electron configuration a. 5s 2 5p^1 b. 3s 2 3p^5 c. 3s 2 3p^3 d. 5s 2 5p^3 17. Which electron configuration is impossible? a. 1 s 2 2s 2 2p^6 3s 2 b. 1s 2 2s 2 2p^6 3s 2 3p^6 c. 1s 2 2s 2 2p^6 2d^2 d. 1s 2 2s 2 2p^5 3s 1 18. The element X occurs naturally to the extent of 20.0% 12 X and 80.0% 13 X. The atomic mass of X is nearest
a. 12. b. 12. c. 12. d. 13.
19. Which electron transition is associated with the largest emission of energy?
a. n=2 to n= b. n=2 to n= c. n=2 to n= d. n=3 to n=
20. If an electron moves from one energy level in an atom to another energy level more remote from the nucleus of the same atom a. energy is absorbed. b. energy is liberated. c. there is no energy change. d. the atom must assume a different ionic valence e. light of a definite wave length is emitted. 21. A photon of light of 450 nm, when compared to light of wavelength 300 nm, has (1nm = 10 -9^ m)
a. a higher frequency. b. lower energy. c. a greater velocity. d. a shorter wavelength
22. Which set of quantum numbers is possible for an electron in an atom?
a. n=3, l=0, ml=1, ms = - ½ b. n=2, l=2,ml= -2, ms = - ½ c. n=5, l=2, ml=2, ms =+ ½ d. n=4, l=3, ml= -4, ms = - ½
23. A compound consisting of an element having a low ionization potential and a second element having a high electron affinity is likely to have
a. covalent bonds b. metallic bonds c. coordinate covalent bonds d. ionic bonds.
24. According to modern bonding theory the number of sigma (σ) and pi ( π ) bonds in the ethylene molecule H (^) 2C=CH 2 is a. l π and 4 σ b. l π and 1 σ c. l π and 5 σ d. 2 π and 4 σ e. l π and 6 σ
H 2 are not provided. d. will have the same value as the K (^) eq for 2 H2(g) + O2(g)!" 2 H2O(l)
35. Consider the reversible system at equilibrium: 2CO + O 2 !" 2CO 2 + heat When the temperature is increased at constant pressure
a. the CO 2 concentration will be increased. b. the CO 2 concentration will be decreased. c. the amount of each substance will be unchanged. d. the amount of each substance will be increased. e. the result cannot be predicted from the information given.
36. The numerical value of the equilibrium constant for any chemical change is affected by changing a. the catalyst. b. the concentration of the products. c. the concentration of reacting substances. d. the pressure. e. the temperature 37. What is the equilibrium constant expression for the gas phase oxidation of CO to CO 2 by O2?
a. K = [CO 2 ] 2 [CO][O 2 ]
b. K= [CO] 2 [O 2 ] [CO2]
c. K= [CO 2 ] 2 [CO] 2 [O2]
d. K= [CO] [O 2 ] [CO2]
38. Into an empty vessel COCl 2 (g) is introduced at 1.0 atm pressure whereupon it dissociates until equilibrium is established: 2COCl (^) 2(g) !" C (graphite) + CO 2 (g) + 2Cl (^) 2(g)
If x represents the partial pressure of CO 2 (g) at equilibrium, what is the value of the equilibrium constant, Kp? a. x.2x 2 (1.0-2x) 2
b. x x 2x^2 (1.0-2x 2 ) c. x (2x) 2 (1.0- 2x) 2 d. x (2x) 2 (1.0—x) 2
39. At a certain temperature, the equilibrium constant for the reaction 2HI(g) !"""" H2(g) + I2(g) is 0.49. Calculate the number of moles of hydrogen produced when one mole of HI is placed in a 1 L vessel at this temperature. a. 0. b. 0. c. 0. d. 3. 40. What is the [OH-] of a solution which is 0.18 M in ammonium ion and 0.10 M in ammonia? Kb = 1.8 x 10 - a. 1.3x10- b. 1.0x10 - c. 1.3x10 - d. 1.0x10 - 41. What is the pH of a 0.10 M solution of a monoprotic acid, HA, with a Ka = 1.0 x 10 -6? a. 1. b. 3. c. 5. d. 6. 42. When 0.10 mol of a weak acid HA was diluted to one liter, experiment showed the acid to be 1% dissociated. HA + H2O !" H3O+^ + A - What is the acid dissociation constant, Ka? a. 1 x10 - b. 1 x10 - c. l x10- d. 1 x10 5 43. Which solution has a pH less than 7.0? a. 1 M NH 4 Cl b. 1 M K 2 CO 3 c. 1 M NaOCl d. 1 M NaOH 44. What is the pH of a 0.1 M NaF solution? Ionization constant for HF, Ka = 7 x 10 - a. 2. b. 5. c. 8. d. 9.
45. What is the hydrogen ion concentration of a buffer solution containing 0.10 M NO 2 1-^ and 0. M HNO 2? Ionization constant for Nitrous Acid, Ka = 4.5x 10 -
a. 2.2x10 -4M b. 9.0 x 10 -4^ M c. 4.5 x 10 -4^ M d. 9.5 x 10 -3M
46. The solubility of BaCO 3 is 7.9 x 10 -3^ g/L. Calculate the solubility product, Ksp ignoring hydrolysis. MW of BaCO 3 197 g/mol
a. 1.6x10 - b. 1.6x10 - c. 4.0x10 - d. 6.2x10 -
47. The addition of solid Na (^) 2SO 4 to an aqueous solution in equilibrium with solid BaSO 4 will cause
a. no change in [Ba 2+] in solution. b. more BaSO 4 to dissolve. c. precipitation of more BaSO4. d. an increase in the K (^) sp of BaSO4.
48. Assume that standardized aqueous solutions of each of these are available.
Substance Ionization Constant NaOAc Kb = 5.6 x 10 - RNH 3 +^ Cl -^ Ka = 5.6 x 10 - RNH 2 Kb=1.8x10- HOAc Ka=1.8x10-
A buffer with a desired pH is 5.0 would be conveniently prepared by appropriate mixtures of a. NaOAc and HOAc b. HOAc and water c. NaOAc and RNH 2 d. HOAc and RNH 2
49. Which substance is most soluble in water? a. C6H 6 b. CaCO 3 c. C2H5OH d. CO 2 50. The solubility of BaCrO 4 in water is 2.8 x 10 -3^ g/L what is the K (^) sp of the salt? MW of
BaCrO 4 253 g/mol a. 1.2x10 - b. 2.2x10 - c. 2.8x10 - d. 7.8 xl0 -
51. Which is the correct expression for the solubility product constant for Ag2CrO 4? a. Ksp = [Ag+] 2 [CrO 4 2-] b. Ksp = [2Ag+] 2 [CrO 4 2-] c. Ksp = [Ag+] [CrO 4 2-] d. Ksp = [Ag+] [CrO 4 2-] 2 e. Ksp = [2Ag+] [CrO 4 2-] 52. The correct IUPAC name of N 2 O 3 is a. nitrogen oxide. b. nitrogen(II) oxide. c. nitrous oxide d. dinitrogen trioxide. 53. In which case is the substance with the given formula followed by its correct name? a. KNO 2 — potassium nitrate b. FeCl 3 — iron(III) chloride c. FeS — iron(II) sulfite d. Mg3N 2 — magnesium nitrite e. HClO — hydrochloric oxide 54. Balance the equation for the following reaction, using no fractional coefficients.
? C +? HNO 3 """"? CO 2 +? NO 2 +? H 2 O
The sum of the coefficients in the balanced equation is a. 5 b. 7 c. 9 d. 12 e. 16
55. Complete and balance the equation for the reaction, where the reactants are in aqueous solution. Use no fractional coefficients.
? Na 3 PO 4 +? Ba(NO 3 ) 2 "? +?
The number of moles and formula of the product containing Ba are a. 3NaNO 3 b. BaPO 4 c. Ba(PO4) (^2) d. Ba (^) 2P 3 e. Ba (^) 3(PO 4 ) (^2)
66. It is desired to collect enough oxygen over water at 25 oC and 750 mmHg barometric pressure to be equivalent to 1 L of pure oxygen at 0 oC and 760 mmHg. The vapor pressure of water at 25 oC is 23.5 mm. The volume collected is a. 1 L (298/273)(750/760) b. 1 L (273/298)((750-23.5)/(760-23.5)) c. 1 L (273/298)((750-23.5)/760) d. 1 L (298/273)(760/(750-23.5)) 67. Methane, CH4, diffuses in a given apparatus at the rate of 30 mL/min. At what rate would a gas with a molar mass of 100 diffuse under the same conditions? MW of CH 4 = 16 g/mol a. 0.77 mL/min b. 30 mL/min c. 6.7 mL/min d. 75 mL/min e. 12.0 mL/min 68. The Arrhenius equation, k= Ae -E/RT expresses the relationship between the reaction rate constant, k, and the energy of activation, E_._ The probability that colliding molecules will react a. increases with increasing energy of activation. b. depends only on the empirical constant, A. c. increases with decreasing temperature. d. decreases with increasing energy of activation. 69. The rate law for the reaction A+B"C+D is first order in [A] and second order in [B]. If [A] is halved and [B] is doubled, the rate of the reaction will
a. remain the same b. be increased by a factor of 2. c. be increased by a factor of 4. d. be increased by a factor of 8.
70. The addition of a catalyst in a chemical reaction a. increases the concentration of products at equilibrium. b. increases the fraction of reactant molecules with a given kinetic energy. c. provides an alternate path with a different activation energy. d. lowers the enthalpy change in the overall reaction. 71. The following mechanism has been proposed for the formation of ethylbenzene:
CH 3 CH2Br + AlBr 3 " AlBr 4 -^ + CH 3 CH 2 + CH 3 CH 2 +^ + C6H 6 " C6H6CH2CH 3 + C6H6CH2CH 3 +^ + AlBr 4 -^ "AlBr 3 + HBr + C6H5CH2CH 3
Which substance serves as the catalyst?
a. AlBr (^3) b. CH3CH 2 + c. AlBr 4 - d. C6H 6 CH2CH 3 +
72. Which substance has the highest boiling point?
a. CH 4 b. He c. HF d. Cl (^2)
73. The table presents data for the reaction: The temperature of the reaction is constant. The initial rate is in arbitrary units. 2H2(g) + 2NO(g) " 2H 2 O(g) + N 2 (g)
Initial Concentration (mol/L) Exp. [NO] x 10-3^ [H2] x 10 -3^ Initial Rate I 6.0 1.0 18 II 6.0 2.0 36 III 1.0 6.0 3 IV 2.0 6.0 12
What is the rate law for this reaction? a. rate = k 1 [H2][NO] b. rate = k 1 [H 2 ] 2 [NO] 2 c. rate = k 1 [H 2 ] 2 [NO] d. rate = k 1 [H2] [NO] 2
74. The reaction 2A + 2B """" C +D proceeds by this mechanism:
2A !" A 2 (equilibrium) A 2 + B """" X + C (rate determining) X+B"D (rapid) The rate equation for the reaction is
a. rate = k[A] [B] b. rate = k[A] 2 [B] 2 /[C][D] c. rate = k[A] 2 [B] 2 [D] d. rate = k[A] 2 [B]
75. What is the correctly reported mass of water based on this data?
Mass of beaker and water 29.62 g Mass of beaker only 28.3220 g
a. 1.3g b. 1.30g c. 1.298g d. 1.2980g
76. When a small single piece of magnesium ribbon is dropped into a test tube half filled with dilute sulfuric acid, the metal soon floats to the surface of the liquid. The best explanation for this is that, (Densities, Mg, 1.79 g/cm^3 ; H2SO 4 (dilute) 1.2 g/cm^3 )
a. the metal is less dense than the acid. b. the metal gets hot and expands and decreases its density markedly as it reacts with the acid c. the magnesium sulfate formed increases the density of the solution. d. gas bubbles attached to the metal buoy the metal to the top. e. convection currents set up in the acid carry the metal to the top.
77. The equilibrium vapor pressure of a few liters of a liquid is dependent on
a. the mass of the liquid. b. the surface area of the liquid c. the temperature only d. the volume of the liquid
78. The edge of a unit cube of an element Y, containing two atoms per unit cube, was found (by X- ray diffraction) to be 3.16 x 10 -8^ cm. The density of the metal is 19.35 g/cm^3. What is the approximate atomic molar mass of Y?
a. 65. b. 92. c. 184 d. 238
79. When a hypothetical ionic crystal M+X -^ is heated, it vaporizes to form separate M +(g) and X - (g) ions. The energy required for this vaporization (the lattice energy) will be greatest when
a. the electron affinity of X is small in magnitude and the ionization potential of M is large in magnitude. b. the heat of vaporization of crystalline M is small. c. the heat of vaporization of crystalline M is large. d. the effective radii of M +^ and X -^ are large. e. the effective radii of M +^ and X -^ are small.
80. The stronger the intermolecular forces in a substance
a. the higher the boiling point. b. the lower the boiling point. c. the higher the vapor pressure. d. the smaller the deviation from ideal gas behavior.
81. Which group of substances is correctly arranged in order from the highest to the lowest melting point?
a. HF>H2>NaF b. NaF>H2>HF c. HF>NaF>H 2 d. NaF>HF>H 2
82. The fact that H 2 O has a dipole moment suggests that the water molecule is
a. dimeric b. symmetrical. c. bent. d. nonpolar.
83. Which pair is geometrically similar?
a. SO 2 and CO 2 b. CO 2 and OF 2 c. PH 3 and BF 3 d. SO 2 and O 3
84. The bond type and molecular polarity of SiCl 4 are
Bond Type Polarity of Molecule a. polar nonpolar b. polar polar c. nonpolar polar d. nonpolar nonpolar
96. The reaction between acetic acid and ethyl alcohol is classified as
CH3COOH + C (^) 2H5OH (^) """" CH3COOC 2 H 5 + H 2 O
a. saponification b. addition c. esterification d. hydrolysis
97. Manganese has the oxidation number of + in
a. [MnF (^) 6] 3- b. Mn (^) 2O 7 c. [MnO4] 2- d. [Mn(CN) (^) 6] 1-
98. The highest oxidation number of vanadium is exhibited in
a. VO2+ b. VBr (^4) c. NH4VO 3 d. V (^) 2(SO4) (^3) e. V(CN) 6 3—
99. Fe(s) + Cu2+^ (aq) """" Cu(s) + Fe 2+^ (aq) Which statement is true for the reaction?
a. Cu 2+^ is oxidized. b. Cu2+^ gains in oxidation state. c. Cu2+^ is reduced. d. Fe(s) is reduced.
100. Which is the strongest oxidizing agent?
Standard Potentials Eo Na " Na +^ + e 2.71 V Cd " Cd2+^ + 2e 0.40 V H 2 " 2H+^ + 2e 0.00 V Ag "Ag+^ + e -0.80 V
a. Na + b. H 2 c. Cd^0 d. Ag+
101. In this reaction
3Mg + 2HNO (^) 3(dilute) + 6H" 3Mg2+^ + 2NO + 4H (^) 2O
the magnesium acts as a reducing agent. How many electrons does each magnesium atom lose?
a. 1 b. 2 c. 3 d. 4 e. 6
102. Which of these isoelectronic ions is the most polarizable?
a. Na + b. O2- c. F- d. Mg2+
103. The greatest oxidizing power (tendency to gain electrons) is shown by
Standard Potentials E o Na" Na +^ + e 2.714 V Al " Al 3+^ +3e 1.67 V Sn 2+^ "Sn 4+^ +2e -0.14 V 21 —^ " l (^) 2+2e -0.535 V 2F—"F 2 + 2e -2.85 V a. Na + b. Al c. Sn 4+ d. F 2
104. Which metal will reduce copper(ll) ions but not zinc ions?
Standard Potentials E o Na " Na +^ +e 2.71 V Zn " Zn2+^ +2e 0.76 V Fe " Fe 2+^ + 2e 0.4 V Pb " Pb2+^ +2e 0.13 V H 2 " 2H+^ + 2e 0.00 V Cu " Cu2+^ +2e -0.34.V Hg " Hg2+^ +2e -0.85 V Ag " Ag+^ +e -0.80 V
a. Na b. Hg c. Pb d. Ag
105. A metal, M, forms an oxide of formula M (^) 2O3. The ground state valence shell electron configuration of the M atom is
a. ns 2 np^1 b. np 6 c. 4s 1 3d^10 d. 4f 7
106. From your knowledge of the periodic nature of the elements, what formula would be anticipated for gallium selenide?
a. GaSe b. GaSe (^2) c. Ga (^) 2Se d. Ga (^) 2Se (^3)
107. Use this section of a periodic table. A E Q R If atoms of R have one “d” type electron, what is the formula for a nitride of element A?
a. A3N b. A3N 2 c. AN d. AN 2
108. In which pair of particles is the first member larger than the second member?
a. Li +^ ; Be 2+ b. Li +^ ; Na+ c. Li +^ ; Li d. Be ; Mg
109. Which would be expected to be the most electronegative?
a. P b. As c. Si d. Al
110. Predict which element would have the largest difference between its first and second ionization energies. a. Sodium b. Phosphorus c. Silicon d. magnesium 111. In which reaction is the energy term referred to as the ionization energy?
a. NaCl(crystal) + energy (^) """" Na +^ (g) + Cl —^ (g) b. Cl(g) + energy "Cl +^ + e c. Cl(g) + e """" Cl —(g) + energy d. Cl —^ g) + H+^ (g) """" HCl(g) + energy
112. Based on their positions in the periodic table, which is most likely to replace selenium, Se, in a biological system? a. Te b. Br c. As d. I 113. Which conditions favor the high solubility of a gas in a liquid? a. high pressure, high temperature b. high pressure, low temperature c. low pressure, high temperature d. low pressure, low temperature 114. Ionic compounds in the solid state at room temperature are generally characterized by their a. ability to conduct an electric current. b. high vapor pressures. c. solubility in polar solvents. d. solubility in nonpolar solvents. e. low melting points. 115. Which precipitate will not dissolve in aqueous HCl solution? a. AgBr b. BaCO 3 c. CaSO 3 d. Fe(OH) (^3) e. ZnS 116. A cellophane bag, which acts as a membrane permeable only to water, contains a 2 M sugar solution. The bag is immersed in a 1 M sugar solution. What will happen?
a. The bag will soon contain more solution that will be are concentrated than 2 M. b. The bag will soon contain more solution that will be less concentrated than 2 M. c. The bag will lose sugar and the solution in it will become less concentrated. d. The bag will lose water and the solution in it will become more concentrated. e. There will be no change.
127. A 6.80 g coin was dissolved in nitric acid and 6.21 g of AgCl was precipitated by the addition of excess sodium chloride, Calculate the percentage silver in the coin.
Ag+(aq) + Cl 1-^ (aq) " AgCl(s)
a. 24.7% b. 68.7% c. 75.3% d. 91.3%
128. A 40- mL portion of a 0.1 M MgSO 4 solution contains how many grams of MgSO4? a. 120 g b. 24 g c. 0.96 g d. 0.6 g e. 0.48 g 129. An aqueous solution containing 49 g of sulfuric acid per liter has a concentration of a. 0.50 M b. 1.0M c. 4.9% by mass d. 4.9M 130. One hundred milliliters of a solution of oxalic acid, (COOH) (^) 2, is neutralized with 50. mL of 0.750 M KOH solution. What is the molarity of the oxalic acid solution? a. 0.099 M b. 0.375 M c. 0.188 M d. 0.750 M e. 0.333 M 131. How many L of CO 2 gas at STP can be obtained by burning one mole of C 3 H 8? C3H8(g) + 5 O2(g) "3 CO 2 (g) + 4H 2 O(g) a. 11. b. 44. c. 67. d. 112 132. What volume of ammonia gas, NH (^) 3, measured at STP, will be produced by the decomposition of two moles of ammonium carbonate? (NH4) 2 CO 3 (s) """" 2NH3(g) + CO 2 (g) + H 2 O(g) a. 22.4 L b. 33.6 L c. 44.8 L d. 89.6 L e. 112 L 133. Which change is likely to be accompanied by the greatest increase in entropy?
a. N 2 (g) + 3H2(g) """" 2NH3(g) (at 25 oC ) b. Ag+^ (aq) + Cl 1-(aq) """" AgCl(s) (at 25 oC ) c. CO2(s) """" CO 2 (g) (at - 70 oC ) d. H 2 O(g) """" H2O(l) (at 100 oC)
134. When 45.0 g of an alloy at 100.0 oC is dropped into 100.0 g of water at 25.0 oC the final temperature is 37.0 oC. What is the specific heat of the alloy? (for water, specific heat = 4.184 J g- 1 o (^) C-1) a. 0.423 J g-1 o^ C- b. 1.77 J g-1 o^ C- c. 9.88 J g-1 o^ C- d. 48.8 J g-1 o^ C- 135. What is the standard enthalpy of combustion of C2H 6 in kJ mol -1?
Reaction (^) ∆∆∆∆ H o H2(g) + ½ O2(g) " H 2 O (^) (l) -286 kJ C2H4(g) + H2(g) " C2H (^) 6(g) -137 kJ C 2 H (^4) (g) + 3 O (^) 2(g) " 2 CO (^) 2(g) + 2 H (^) 2O (^) (g)
-1412 kJ
a. –1275 kJ b. –31561 kJ c. –1558 kJ d. +1834 kJ
136. Given these equations SO2(g) " O2(g) + S (s) ∆Ho^ = +300 kJ 2SO 2 (g) + O 2 (g) """" 2SO3(g) ∆Ho^ = - 200 kJ
calculate the heat of formation of SO 3 (g). a. –500 kJ.mol - b. +100 kJ.mol - c. –400 kJ.mol - d. +200 kJ.mol -
137. More heat is derived from cooling one gram of steam at 100 oC to water at 50 oC than from cooling one gram of liquid water at 100 oC to 50 oC because
a. water is a poor thermal conductor. b. the steam is hotter than the water. c. the steam occupies a greater volume than the water. d. the density of water is greater than that of steam. e. the heat of condensation is evolved.
138. Calculate the value of (in kJmol -1) for the reaction
N2(g) + 3H 2 (g) "2NH3(g)
Bond Energies (kJ. mol -1) H—H 435 N=N 946 (in N2) N—H 389
a. 2340 kJ of heat absorbed b. 213 kJ of heat absorbed c. 2340 kJ of heat evolved d. 83 kJ of heat evolved
139. When Al (^) 2O3(s) is formed from the elements at standard conditions, the values of ∆Η o^ and ∆Go at 298 K are -1617 kJ.mol -1^ and -1577 kJ.mol -1, respectively. The standard entropy of formation per mole, in joules per degree, will be a. - b. - c. - 93. d. 0. e. +15. 140. Vaporization of a liquid is an example of a process for which a. ∆H, ∆S, and ∆G are positive at all temperatures. b. ∆H and ∆S are positive. c. ∆G is negative at low temperatures, positive at high temperatures. d. ∆H=∆S 141. Consider the boiling point of a series of hydrogen compounds. The abnormally high boiling point for water is due to
BP
H2O H2S H2Se H2Te
a. extensive hydrogen bonding b. its low dipole moment. c. the extreme stability of the compound. d. the high electronegativity of hydrogen.
142. Which nuclear equation is properly balanced? a.^4 He + 9 Be " 12 C + 1 H b.^4 He + 14 N " 17 O + 1 H c.^4 He + 24 Mg " 27 Si + 1 H d.^14 N + (^0) -1e " 14 O 143. What is the correct reading for the buret? 32
a. 32 mL b. 32.2 mL c. 32.26 mL d. 33.74 mL
144. A particular chemical reaction has a negative ∆H and negative ∆S. Which statement is correct?
a. The reaction is spontaneous at all temperatures. b. The reaction is nonspontaneous at all temperatures. c. The reaction becomes spontaneous as temperature increases. d. The reaction becomes spontaneous as temperature decreases.
145. Which line in the diagram represents the activation energy for a forward reaction?
a. A A D b. B E c. C d. D B C
Reaction Coordinate
H
146. The group —C=O is characteristic of a. aldehydes. b. ketones. c. alcohols d. esters e. acids
Vapor pressure mm Hg
153. For the reaction 2H2O 2 "2H 2 O +O 2 Which plot confirms that the rate is first order with respect to H2O2?
a. b. c. d.
[H2O2] 1/[H 2 O2] [H 2 O2] 2 log[H2O2]
time time time time
154. Sulfur dioxide can be described by the structures:
S S O O O O This implies that
a. the two bonds in SO 2 are of equal length, and the electronic distribution in the two SO bonds is identical. b. the single bond is longer than the double bond and the electronic distribution in the two SO bonds is different. c. an electron pair in the SO 2 molecule alternates back and forth between the two sulfur— oxygen electron pairs so that the two different bonds seem to exchange positions. d. the SO 2 molecule revolves so that the two different bonds seem to exchange positions.
155. The graph shows how the vapor pressure of liquid A and of liquid B changes with the temperature. Select the choice that best indicates the degree of correctness of this statement: “The normal boiling point of liquid B is 78 0 C.”
A
B
Temperature o^ C
a. The statement is true. b. The statement is probably true; additional data would be needed for a final decision. c. It is impossible to judge the statement because data are insufficient. d. The statement is probably false; additional data would be needed for a final decision. e. The statement is false.
156. The isomerism represented by H H H H H H
H— C—C—C—O—H and H—C—C—O—C—H
H H H H H H
a. cis—trans. b. optical. c. positional. d. geometric.
157. In a sample of a nearly ideal gas, this graph could represent a plot of
a. V vs. T at a given constant P. b. P vs. T at a given constant V. c. P vs. V at a given constant T d. PV vs. P at a given constant T
158. A mixture of 100 g of K 2 Cr 2 O 7 and 200 g of water is stirred at 60 oC until no more of this salt dissolves. The resulting solution is decanted (poured off) and cooled to 20 oC. What mass of K (^) 2Cr 2 O 7 crystallizes from the solution during the cooling?
80
Solubility (g/100 mL) 40
20
Temperature in oC a. 24 g b. 31 g c. 43 g d. 58 g e. 86 g
159. The height of the mercury in the right arm open to atmospheric pressure (760 mmHg) is 100 mm and the height in the left arm is 120 mm.
gas What is the pressure of the gas in the bulb?
a. 20 mmHg b. 640 mmHg 120 mm c. 740 mmHg 100 mm d. 780 mmHg
