Chem acs final

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A 2.50 L sample of butane gas (C4H10), measured at 22.0 oC and 1.20 atm pressure, is combusted completely and the carbon dioxide gas collected at the same pressure and temperature. What volume of CO2 is produced?

10.0L

In a sample consisting of 1.00 mol NaBr and 0.300 mol KI, what is the mass percent of iodine? (A) 24.9% (B) 32.6% (C) 47.2% (D) 83.1%

What is the Ksp of Hg2Cl2 at 298 K? (A) 2.6 10-17 (C) 5.1 10-9 (B) 3.3 10-11 (D) 5.7 10-6

What is the electron configuration of the Al3+ ion? (A) 1s22s22p6 (B) 1s22s22p63s23p1 (C) 1s22s22p63s23p4 (D) 1s22s22p63s23p6

What is the formula of the most stable oxide of francium? (A) Fr2O (B) FrO (C) Fr2O3 (D) FrO2

Which is formed at the cathode during the electrolysis of aqueous AgF? (A) Ag(s) (B) H2(g) (C) O2(g) (D) F2(g)

Which resonance structure contributes the most to the overall bonding in nitrous oxide, N2O?

Which salt dissolves in water to give a pink solution? (A) Co(CH3COO)2 (B) CuSO4 (C) Fe(NO3)3 (D) ZnCl2

A coordination complex M(NH3)2Cl2 can be separated into a pair of geometric isomers. Is this observation consistent with a tetrahedral or a square planar geometry at the metal center? (A) It is consistent only with a tetrahedral geometry. (B) It is consistent only with a square planar geometry. (C) It is consistent with either a square planar or a tetrahedral geometry. (D) It is consistent with neither a square planar nor a tetrahedral geometry.

A sample of O2 gas at a given temperature and pressure has a density of 1.30 g L-1. What is the density of gaseous propane (C3H8) under the same conditions? (A) 1.30 g L-1 (B) 1.79 g L-1 (C) 1.96 g L-1 (D) 2.60 g L-1

An irreversible reaction, A + B → products, is studied under conditions where [B] >> [A]. When [B] = 0.10 M, a plot of 1/[A] vs. time is linear. When [B] = 0.30 M, the plot of 1/[A] vs. time is indistinguishable from the first plot within experimental error. What is the rate law for this reaction? (A) Rate = k[A][B] (C) Rate = k[A]2[B] (B) Rate = k[A]2 (D) Rate = k[A][B]2

An unknown monoprotic carboxylic acid RCOOH is mixed in a 1:1 mole ratio with its sodium salt, Na(RCOO). A 1.000 g sample of this 1:1 mixture is dissolved in 50 mL water and titrated with 0.5000 M NaOH solution. The pH is measured as a function of added titrant to give the following titration curve: Which statements are correct? I. The molar mass of RCOOH is within 5% of 265g/mol-1 II. The pKa of RCOOH is within 0.1 unit of 4.2. (A) I only (B) II only (C) Both I and II (D) Neither I nor II

As atomic number increases from 11 to 15, the atomic radii of the elements (A) increase (B) decrease (C) increase, then decrease (D) decrease, then increase

Benzene, C6H6, reacts with oxygen, O2, to form CO2 and H2O. How much O2 is required for the complete combustion of 1.0 mol C6H6? (A) 6.0 mol (b)7.5 mol (C) 9.0 mol (D)12 mol

Bromate ion and bromide ion react to form bromine in acidic solution. When the reaction is balanced, which statement about H+(aq) is correct? H+(aq) + BrO3-(aq) + Br-(aq) → Br2(aq) + H2O(l) (A) Its coefficient is twice the coefficient of Br-(aq). (B) Its coefficient is twice the coefficient of Br2(aq). (C) Its coefficient is twice the coefficient of BrO3-(aq). (D) Its coefficient is the sum of the coefficients of BrO3- (aq) and H2O(l).

Calcium fluoride, CaF2, has a molar solubility of 2.1 10-4 mol L-1 at pH = 7.00. By what factor does its molar solubility increase in a solution with pH = 3.00? The pKa of HF is 3.17. (A) 1.48 (B) 1.83 (C) 2.48 (D) 4.96

How many unpaired electrons are in the superoxide ion, O2- ? (A) Zero (B) One (C) Two (D) Three

In the Lewis structure of the chlorate ion, ClO3-, how many lone pairs of electrons does the chlorine atom have? (A) 0 (B) 1 (C) 2 (D) 3

Addition of small amounts of which solids to 4 M HCl will result in gas evolution? I. Zn II. Na2SO3 (A) I only (C) Both I and II (B) II only (D) Neither I nor II

An electrolytic cell consists of two copper electrodes immersed in a solution of copper(II) sulfate. What is the result of passing 0.35 A of current through this cell for 1300 s? (A) The mass of the anode increases by 0.15 g. (B) The mass of the anode increases by 0.30 g. (C) The mass of the anode decreases by 0.15 g. (D) The mass of the anode decreases by 0.30 g.

An orbital has the radial wavefunction shown below. What orbital is it? C) 3S

At 280 oC, nitrogen dioxide decomposes to nitric oxide and oxygen: 2 NO2(g) 2 NO(g) + O2(g) In one experiment, the concentration of NO2 decreased from 0.0100 M to 0.0050 M over the course of 100. s. What was the average rate of disappearance of NO2(g)? (A) 1.010-2 Ms-1 (C) 5.010-5 Ms-1 (B) 1.010-4 Ms-1 (D) 2.510-5 Ms-1

Thallium-201, a radioactive isotope used to image the heart, has a half-life of 3.05 d. How long would it take for a sample of thallium-201 to decay to 18% of its original activity? (A) 4.4d (B) 6.1d (C) 7.5d (D) 17d

The electronegativity of gallium (1.8) is greater than that of aluminum Which is the best explanation for this difference? (A) Ga is larger than Al, so its valence electrons experience less electron-electron repulsion. (B) Ga has more protons than Al, so its valence electrons are more attracted to the nucleus. (C) Ga has a filled 3d subshell, whose electrons incompletely screen the nucleus. (D) Ga experiences significant relativistic effects, which contract the valence orbitals.

The enthalpy of formation of XeF2(g) is -108 kJ mol-1 and the bond dissociation enthalpy of the F-F bond is 155 kJ mol-1. What is the average bond dissociation enthalpy of a Xe-F bond? (A) 47 kJ mol-1 (C) 132 kJ mol-1 (B) 54 kJ mol-1 (D) 263 kJ mol-1

The formula for terbium phosphate is TbPO4. The formula for terbium sulfate is (A) Tb2SO4 (C) Tb2(SO4)3 (B) TbSO4 (D) Tb(SO4)2

To 100.0 g water at 25.00 oC in a well-insulated container is added a block of aluminum initially at 100.0 oC. The temperature of the water once the system reaches thermal equilibrium is 28.00 oC. What is the mass of the aluminum block? (The specific heat capacity of Al is 0.900 J g-1 K-1.) (A) 4.17g (B) 18.6g (C) 19.4g (D) 130.g

What is the Ksp of Ca(OH)2 at 298 K? (A) 1.6 × 10-6 (C) 8.4 × 10-6 (B) 3.1 × 10-6 (D) 2.9 × 10-3

What is the molecular geometry of IF3? (C) T-shaped

What is the rate law for the following reaction? A+2BC+D (C) Rate = k[A][B]

What is the standard cell potential of the following electrochemical cell? Ni(s) | Ni2+(aq), 1.0 M || Ag+(aq), 1.0 M | Ag(s) (A) -1.83 V (B) 0.57 V (C) 1.03V (D) 1.83 V

Which aspect of metallic bonding best accounts for the characteristic malleability of metals? (A) Metals have few valence electrons. (B) Metals contain a lattice of positive ions. (C) Metals contain delocalized electrons. (D) Metals have low electronegativity.

Which calcium compound is not appreciably more soluble in 0.1 M hydrochloric acid than it is in pure water? (A) Limestone, CaCO3 (B) Slaked lime, Ca(OH)2 (C) Gypsum, CaSO4 • 2 H2O (D) Hydroxyapatite, Ca5(OH)(PO4)3

Which is the best explanation for the negative sign of ∆So in the following reaction? CaSO4(s) Ca2+(aq) + SO42-(aq) ∆So = -143 J mol-1 K-1 A) There are more ways of arranging the Ca2+ and SO42- ions in aqueous solution than in the crystal lattice. (B) Solid CaSO4 is a network covalent solid, whereas it separates into ions in aqueous solution. (C) Aqueous Ca2+ and SO42- ions are tightly solvated, decreasing the number of ways of arranging water molecules when the solid dissolves. (D) Calcium sulfate dissolves exothermically, leading to a net loss of entropy.

Which metal has the highest melting point? (A) K (B) Ca (C) Fe (D) Zn

Which metal reacts most vigorously with water at 25 °C? (A) Na (B) Mg (C) K (D) Ca

Which methods would be suitable for determining the concentration of an aqueous solution of KMnO4? I. Visible spectrophotometry (colorimetry) II. Redox titration (A) I only. (C) Both I and II (B) II only. (D) Neither I nor II

Which molecule has no unpaired electrons? (A) NO (B) O2 (C) SO2 (D)ClO2

Which of the following are true for a spontaneous process in a system at constant temperature and pressure? I. ∆Ssys +∆Ssurr >0 II. ∆Gsys <0 (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Which of the following compounds could contain exactly one triple bond? (A) C5H10 (B) C5H12 (C) C6H10 (D) C6H12

Which structural features contribute to the low strain energy of cyclohexane? I. All bond angles are close to 109.5o. II. All C-H bonds on adjacent carbon atoms are staggered (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Compared to ionic compounds of similar molar mass, hydrocarbons typically have I. Higher water solubility II. Higher melting points (A) I only (B) II only (C) Both I and II (D) Neither I nor II

How many completely filled p orbitals are present in a ground state Cl atom? (A) 1 (B) 2 (C) 4 (D) 5

The bond dissociation enthalpies of the H-H bond and the H-Cl bond are 435 kJ mol-1 and 431 kJ mol-1, respectively. The ∆Hof of HCl(g) is -92 kJ mol-1. What is the bond dissociation enthalpy of the Cl-Cl bond? (A) 88 kJ mol-1 (B) 96 kJ mol-1 (C) 188 kJ mol-1 (D) 243 kJ mol-1

The following data were collected for the reaction of A and B: What is the order of the reaction with respect to A and B? (A) 0th order in A, 2nd order in B (B) 1st order in A, 1st order in B (C) 2nd order in A, 1st order in B (D) 1st order in A, 2nd order in B

The following mechanism is proposed for the oxidation of I- by OCl- in aqueous solution: What reaction orders for OCl-, I-, and OH- are consistent with this mechanism? (A) 1 1 1 (B) 1 1 0 (C) 1 0 0 (D) 1 1 -1

The normal boiling point of 2-propanol, (CH3)2CHOH, is 83 oC, while that of acetone, (CH3)2C=O, is 56 oC. What is the principal reason for the greater boiling point of 2- propanol? (A) The O-H bond in 2-propanol is stronger than the C-H bonds in acetone. (B) 2-Propanol experiences greater London dispersion forces than acetone. (C) 2-Propanol experiences stronger dipole-dipole interactions than acetone. (D) 2-Propanol experiences stronger hydrogen bonding than acetone.

The wavelength of one of the spectral lines of helium is 492 nm. What is the energy of a photon with this wavelength? (A) 3.26 10-40 J (C) 4.04 10-28 J (B) 3.26 10-31 J (D) 4.04 10-19J

To what elements are the phosphorus atoms in DNA bonded? I. C II. H (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Trimesic acid is a triprotic acid with pK1 = 3.1, pK2 = 3.9, and pK3 = 4.7. 100.0 mL of 0.100 M trimesic acid is titrated with 0.500 M NaOH(aq) to give the graph below. What volume of NaOH(aq) has been added at the point marked V on the graph? (A) 5mL (B) 10mL (C) 20mL (D) 30mL

What is observed when equal volumes of 0.1 M aqueous HCl and 0.01 M aqueous Na2SO3 are mixed? (A) Colorless solution and a white precipitate (B) Colored solution and a white precipitate (C) Colorless solution and a colored precipitate (D) Colorless solution, no precipitate, and gas evolution

What is the bond order in NO? (A) 1.0 (B) 1.5 (C) 2.0 (D) 2.5

What is the cell potential of the following galvanic cell under the stated conditions at 298 K? Zn(s) | Zn2+(aq, 1.0 × 10-4 M) AgCl(s) | Ag(s), Cl-(aq, 0.50 M) (A) +0.884 V (C) +1.084 V (B) +0.984 V (D) +1.120 V

What is the concentration of nitrate ion in a 425 mL solution containing 32.0 g of Mg(NO3)2 (M = 148.3)? (A) 0.216 M (B) 0.432 M (C) 0.508 M (D) 1.02 M

What is the ratio Kc/Kp for the following reaction at 723 °C? O2(g) + 3 UO2Cl2(g) U3O8(s) + 3 Cl2(g) (A) 0.0122 (B) 1.00 (C) 59.4 (D) 81.8

What is the relationship between the following two molecules? (A) Structural isomers (C) Enantiomers (B) Geometric isomers (D) Identical

What is the relationship between the two compounds below? CH3CH2CH(CH3)CH2CH3 CH3CH2CH2CH(CH3)CH3 (A) Identical (B) Stereoisomers (C) Geometric isomers (D) Structural isomers

What is the role of hydroxide ion in the reaction below? CH3CH2CH2CH2Br + OH- CH3CH2CH2CH2OH + Br- (A) Oxidizing agent (C) Catalyst (B) Lewis acid (D) Nucleophile

What is the solubility of MgF2 (Ksp = 6.8 10-9) in pure water? (A) 6.8 10-9 mol•L-1 (B) 5.8 10-5 mol•L-1 (C) 8.2 10-5 mol•L-1 (D) 1.2 10-3 mol•L-1

What is ∆Eo for this reaction?2 Ag(s) + Cu2+(aq) + 2 Cl-(aq) → 2 AgCl(s) + Cu(s) (A) -0.115 V (C) 0.107 V (B) -0.107 V (D) 0.115 V

What is ∆Gof of HOCl(g) at 298 K?. H2O(g) + Cl2O(g)---><---2 HOCl(g) (A) -6.0 kJ mol-1 (B) -3.0 kJ mol-1 (C) 3.0 kJ mol-1 (D) It cannot be determined from the information given

Which of the following is a nonelectrolyte in aqueous solution? (A) H2SO4 (C) K2CO3 (B) NaC2H3O2 (D) CH2O

Which of these reactions has ∆S° > 0? (A) S (l) S (s, monoclinic) (B) H2(g) + O2(g) H2O2(aq (C) H2(g) + 2 Ag+(aq) 2 H+(aq) + 2 Ag(s) (D) PCl5(g) PCl3(g) + Cl2(g)

Which piece of equipment would give the most precise delivery of 25.0 mL of a solution? (A) 25-mL graduated cylinder (B) 25-mL syringe (C) 25-mL beaker (D) 25-mL volumetric pipet

Which reaction is not exothermic? (A) Dilution of concentrated hydrochloric acid in water. (B) Dilution of concentrated sulfuric acid in water. (C) Dissolution of solid sodium hydroxide in water. (D) Dissolution of solid sodium bicarbonate in water.

Which solute, when dissolved in 1 kg H2O, will give the solution with the highest boiling point? (A) 50 g ethylene glycol, HOCH2CH2OH (B) 50 g hydroxyacetic acid, HOCH2COOH (C) 50 g glycerol, HOCH2CHOHCH2OH (D) 50 g glyoxal, HCOCHO

Which statements about the behavior of gaseous H2 molecules in a container at 1 atm and 298 K are correct? I. All H2 molecules are moving at the same speed. II. The H2 molecules are colliding more frequently with the walls of the container than they would in the same container at 398 K. (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Which two half reactions, when coupled, will make a galvanic cell that will produce the largest voltage under standard conditions? I. Cu2+(aq)+2e- Cu(s) E = +0.34V (D) III and IV

1.000 g of a weak base is titrated with 1.000 M aqueous HCl to give the data shown. What is the identity of the base? (A) Ammonia, NH3 (pKa of NH4+ = 9.3) (B) Aniline, C6H5NH2 (pKa of C6H5NH3+ = 4.6) (C) Hydroxylamine, NH2OH (pKa of NH3OH+ = 6.0) (D) Trimethylamine, (CH3)3N (pKa of (CH3)3NH+ = 9.8)

A 0.300 M solution of HCl is prepared by adding some 1.50 M HCl to a 500 mL volumetric flask and diluting to the mark with deionized water. What volume of 1.50 M HCl must be added? (A) 100. mL (C) 225. mL (B) 150. mL (D) 250. mL

A 10.00 g sample of a soluble barium salt is treated with an excess of sodium sulfate to precipitate 11.21 g BaSO4 (M = 233.4). Which barium salt is it? (A) BaCl2 (M = 208.2) (B) Ba(O2CH)2 (M = 227.3) (C) Ba(NO3)2 (M = 261.3) (D) BaBr2 (M = 297.1)

A 2.00g sample of ice at 0.0oC is placed in 50.0g of water initially at 25.0 °C in an insulated container. What is the final temperature after the system has achieved equilibrium? (For ice, ΔH ofusion = 6.01 kJ mol-1.) (A) 21.0 oC (B) 21.8 oC (C) 22.5 oC (D) 24.0 oC

A 20.0 g sample of mercury(II) oxide (HgO, M = 216.6) is heated strongly, causing it to decompose to metallic Hg and O2 gas. What volume of O2 gas is produced (measured at STP)? (A) 1.03L (B) 2.07L (C) 4.14L (D) 14.0L

A certain nuclide undergoes beta decay to form 70Ge. If the same nuclide undergoes electron capture instead, what daughter nuclide forms? (A) 70Zn (B) 70Ga (C) 70Ge (D) 70As

A compound with the formula C6H12 does not decolorize bromine in CHCl3 solution. Which compound could this be? (A) Cyclohexane (C) Trans-3-hexene (B) 1-Hexene (D) Cis-3-hexene

A current of 0.44 A is passed through a solution of a ruthenium nitrate salt, causing reduction of the metal ion to the metal. After 25.0 minutes, 0.345 g of Ru(s) has been deposited. What is the oxidation state of ruthenium in the nitrate salt? (A) +2 (B) +3 (C) +4 (D) +6

A solution containing Co(H2O)62+(aq), CoCl42-(aq), and Cl-(aq) at equilibrium at room temperature is initially pink. When heated, the solution turns blue. Then, when Ag+(aq) is added, the solution turns back to pink. Which statements are correct? I. Co(H2O)62+(aq) is pink. II. Formation of CoCl42-(aq) from Co(H2O)62+(aq) and Cl- is exothermic (A) Ionly (B) II only (C) Both I and II (D) Neither I or II

A solution of a salt of which metal produces a bright red color in a flame test? (A) Lithium (C) Potassium (B) Sodium (D) Copper

A student determines the acetic acid concentration of a sample of distilled vinegar by titration of 25.00 mL of the vinegar with standardized sodium hydroxide solution using phenolphthalein as an indicator. Which error will give an acetic acid content for the vinegar that is too low? (A) Some of the vinegar is spilled when being transferred from the volumetric flask to the titration flask. (B) The NaOH solution is allowed to stand for a prolonged period after standardization and absorbs carbon dioxide from the air. (C) The endpoint is recorded when the solution turns dark red instead of faint pink. (D) The vinegar is diluted with distilled water in the titration flask before the NaOH solution is added.

A student wishes to measure 37 mL of a liquid. Which apparatus would be most suitable? (A) 50 mL graduated cylinder (B) 50 mL volumetric pipet (C) 50 mL beaker (D) 50 mL Erlenmeyer flask

A substance decomposes in a first-order reaction with a rate constant of 6.70 10-4 s-1. If the initial concentration of the substance is 1.50 M, what is its concentration after 500. s? (A) 1.07 M (C) 0.335 M (B) 0.503 M (D) 0.128 M

A37.5gpieceofgoldat83.0°Cisaddedto100.gH2O at 22.0 °C in a well-insulated cup. What is the temperature after the system comes to equilibrium? (The specific heat capacity of Au is 0.129 J•g-1•K-1) (A) 22.7 °C (C) 25.0 °C (B) 23.0 °C (D) 52.5 °C

Addition of 1 M HBr to 0.1 M solutions of which compound results in evolution of a colorless gas? (A) NaHSO3 (B) NaHSO4 (C) Ce(NH4)2(NO3)6 (D) KBrO3

Addition of an electron to a gas-phase Si atom results in the release of more energy than addition of an electron to a gas-phase P atom. What is the best explanation for their relative electron affinities? (A) The electron added to Si experiences less electron- electron repulsion than the electron added to P. (B) The electron added to Si enters a lower-energy subshell than the electron added to P. (C) Si is more electronegative than P. (D) Si is smaller than P.

An aqueous solution of potassium sulfate (K2SO4) has a freezing point of -2.24 oC. What is its molality?(Kf = 1.86 oC•m-1) (A) 0.401 m (B) 0.602 m (C) 1.20 m (D) 4.17 m

An electrolysis cell is operated for 3000 s using a current of 1.50 A. From which 1.0 M solution will the greatest mass of metal be deposited? (A) TlNO3 (C) ZnCl2 (B) Pb(NO3)2 (D) In(NO3)3

An element is a solid at room temperature but soft enough to be cut with an ordinary knife. When placed in water, the element reacts violently. What element is it? (A) Na (B) Mg (C) Cu (D) Hg

At 400 K, this reaction has Kp = 8.2 × 10-4. SO3(g)---><--- SO2(g) + 1/2 O2(g) What is Kp at 400 K for the following reaction? 2 SO3(g)---><---- 2 SO2(g) + O2(g) (A) 6.7 × 10-7 (C) 1.6 × 10-3 (B) 8.2 × 10-4 (D) 2.9 × 10-2

At what temperature is the following reaction at equilibrium when all substances are at standard pressure? Assume that entropies and enthalpies of reaction do not vary with temperature. PCl3(g) + Cl2(g)---><---PCl5(g) (A) 506 K

Ethanol has a normal boiling point of 78.3 oC and a standard heat of vaporization (ΔHovap) of 38.6 kJ mol-1. What is the vapor pressure of ethanol at 45.0 oC? (A) NaF (B) NaCl (C) NaBr (D) NaI (A) 0.25 atm (C) 0.87 atm (B) 0.57 atm (D) 0.91 atm

First-generation automobile airbags were inflated by the decomposition of sodium azide (M = 65.02): 2 NaN3(s) → 2 Na(s) + 3 N2(g) What mass of sodium azide would be required to inflate a 16.0 L airbag to a pressure of 1.20 atm at 17 oC? (A) 34.9g (B) 52.4g (C) 78.6g (D) 157g

For an endothermic reaction to be spontaneous under standard conditions at constant pressure at some temperature T, which must be true? (A) The entropy change ∆So must be positive and greater than ∆Ho/T. (B) The entropy change ∆So must be positive and less than ∆Ho/T. (C) The entropy change ∆So must be negative and greater than -∆Ho/T. (D) The entropy change ∆So must be negative and less than -∆Ho/T.

For which element is the +2 oxidation state LEAST common? (A) Al (B) V (C) Fe D) Sm

For which of the following reactions would the yield of products at equilibrium NOT increase at a higher pressure? (A) N2(g) + O2(g) 2 NO(g) (B) Ti(s) + 2 Cl2(g) (C) 2 C2H4(g) + 2 H2O(g) (D) 4 HCl(g) + O2(g) TiCl4(g)2 C2H6(g) + O2(g) 2 H2O(l) + 2 Cl2(g)

For which reaction is ∆Horxn equal to ∆Hof of CaSO3(s)? (A) Ca(s) + 1/8 S8(s) + 3/2 O2(g) → CaSO3(s) (B) 8 Ca(s) + S8(s) + 12 O2(g) → 8 CaSO3(s) (C) 8 Ca(s) + S8(g) + 12 O2(g) → 8 CaSO3(s) (D) CaO(s) + SO2(g) → CaSO3(s)

Glyoxal consists of 41.4% C, 3.5% H, and 55.1% O by mass. What is the empirical formula of glyoxal? (A) CHO (B) CH2O (C) CH2O2 (D) C12HO16

How is the enthalpy of vaporization of a substance related to its enthalpy of fusion? (A) The enthalpy of vaporization is greater than the enthalpy of fusion. (B) The enthalpy of vaporization is equal to the enthalpy of fusion. (C) The enthalpy of vaporization is less than the enthalpy of fusion. (D) There is no general relationship between a substance's enthalpy of vaporization and enthalpy of fusion.

How many nearest neighbors does each silicon atom have in solid Si? (A) 4 (B) 6 (C) 8 (D) 12

How may an enzyme inhibitor decrease the rate of a reaction catalyzed by the enzyme? I. The inhibitor may bind to the enzyme and block the active site. II. The inhibitor may shift the equilibrium of the reaction toward the starting materials. (A) I only (B) II only (C) Both I and II (D) Neither I nor II

How much Sr(OH)2 • 8 H2O (M = 265.76) is needed to prepare 250.0 mL of solution in which [OH-] = 0.100 M? (A) 3.32g (B) 6.64g (C) 9.97g (D) 13.3g

Hydrogenation of an alkene converts it to an (A) alkane . (B) alkyne. (C) alcohol. (D) aldehyde.

In a well-insulated vessel, 50.0 g ice at 0.0 oC is added to 350. g water at 32.0 oC. What is the final temperature when the mixture reaches equilibrium? (The heat of fusion of ice is 334 J g-1.) (A) 18.0 oC (C) 22.0 oC (B) 20.6 oC (D) 28.0 oC

In the galvanic cellAl(s) ǀ Al3+(aq, 1 M) ǀǀ Cu2+(aq, 1 M) ǀ Cu(s) which of the following changes will increase the cell potential? I. Dilution of the Al3+ solution to 0.001 M II. Dilution of the Cu2+ solution to 0.001 M III. Increasing the surface area of the Al(s) electrode (A) I only (C) III only (B) II only (D) I and III only

In this reaction, NOBr2(g) is best described as (A) an intermediate. (B) a product. (C) a homogeneous catalyst. (D) a heterogeneous catalyst.

In which are the ionic solids ranked in order of increasing melting point? (A) KBr<NaCl<NaF<MgO (B) NaF<NaCl<MgO<KBr (C) KBr<NaCl<MgO<NaF (D) MgO<NaF<KBr<NaCl

In which list are the elements in order of increasing first ionization energy? (A) Ca<Si<P<N (B) N<P<Si<Ca (C) Ca<N<P<Si (D) N<Si<P<Ca

Lithium hydrogen carbonate, LiHCO3, decomposes when heated to form Li2O, CO2, and H2O. How many moles of H2O are formed when 0.50 mol LiHCO3 decomposes? (A) 0.25 mol (B) 0.50 mol (C) 0.75 mol (D) 1.0 mol

Nitrous acid, HNO2, has Ka = 4.5 10-4. What is the best description of the species present in a 0.1 M solution of nitrous acid? (A) HNO2(aq) is the predominant species; much smaller amounts of H+(aq) and NO2-(aq) exist. (B) H+(aq) and NO2-(aq) are the predominant species; much smaller amounts of HNO2(aq) exist. (C) Only H+(aq) and NO2-(aq) are present in measurable amounts. (D) HNO2(aq), H+(aq), and NO2-(aq) are all present in comparable amounts.

One Lewis structure of squarate ion, C4O42-, is shown below. Which statement best describes the bond distances in the squarate ion? (A) All carbon-carbon bond distances are the same, and all carbon-oxygen bond distances are the same. (B) There are two distinct carbon-carbon bond distances, but all carbon-oxygen bond distances are the same. (C) There are two distinct carbon-carbon bond distances, and two distinct carbon-oxygen bond distances. (D) There are three distinct carbon-carbon bond distances, and two distinc

Quartz, SiO2, is the most common mineral found on the surface of the earth. What is the best explanation for the fact that quartz is hard and has a high melting point? (A) Quartz crystals are extended structures in which each atom forms strong covalent bonds with all of its neighboring atoms. (B) Quartz crystals consist of positive and negative ions that are attracted to one another. (C) Quartz crystals are formed under extremes of temperature and pressure. (D) Silicon and oxygen atoms are especially hard because of their electronic structure.

Shown below is a Lewis structure of the formamidinium ion. What geometry is exhibited by the two nitrogens in the formamidinium ion? (A) trigonal planar. trigonal planar

Sodium halides crystallize in the rock salt structure, which has a cubic unit cell with four formula units per unit cell. A sodium halide has a density of 2.83 g cm-3 and a unit cell edge length of 462 pm. Which compound is it? (A) NaF (B) NaCl (C) NaBr (D) NaI

Sulfur trioxide is formed from the reaction of sulfur dioxide and oxygen:SO2(g) + 1⁄2 O2(g)---><---- SO3(g) At 1000 K, an equilibrium mixture has partial pressures of 0.562 bar SO2, 0.101 bar O2, and 0.332 bar SO3. What is the equilibrium constant Kp for the reaction at this temperature? (A) 1.86 (B) 3.46 (C) 5.85 (D) 16.8

Sulfuryl chloride is in equilibrium with sulfur dioxide and chlorine gas: SO2Cl2(g) SO2(g) + Cl2(g) A system with a volume of 1.00 L is in equilibrium at a certain temperature with p(SO2Cl2) = 1.00 bar and p(SO2) = p(Cl2) = 0.10 bar. By how much will the number of moles of SO2Cl2 at equilibrium change if the volume is reduced to 0.50 L? (A) Increase 1-10% (C) Decrease 1-10% (B) Increase 11-50% (D) Decrease 11-50%

The Ka of phosphoric acid, H3PO4, is 7.6 10-3 at 25 °C. For the reaction H3PO4(aq) H2PO4-(aq) + H+(aq) ∆H° = -14.2 kJ/mol. What is the Ka of H3PO4 at 60 °C? (A) 4.2 10-3 (C) 8.5 10-3 (B) 6.8 10-3 (D) 1.8 10-2

The Ksp of Al(OH)3 is 2.0 10-31 at 298 K. What is ∆Go (at 298 K) for the precipitation of Al(OH)3 according to the equation below? Al3+(aq) + 3 OH-(aq) Al(OH)3(s) (A) -175 kJ mol-1 (C) 70.6 kJ mol-1 (B) 14.7 kJ mol-1 (D) 175 kJ mol-1

The Ksp of BaSO4 at 298K is1.1×10-10. What is ∆Go at 298 K for the following reaction? Ba2+(aq) + SO42-(aq) BaSO4(s) (A) -57 kJ mol-1 (C) 25 kJ mol-1 (B) -25 kJ mol-1 (D) 57 kJ mol-1

The boiling points of the alkali metals decrease from lithium to cesium. Which trend is most closely related to the decreasing boiling points? (A) Increasing atomic radius down the group (B) Increasing atomic mass down the group (C) Decreasing electronegativity down the group (D) Decreasing electron affinity down the group

The bond distance in CO is 112.8 pm, while the bond distance in NO is 115 pm. Which is the best explanation for the shorter bond in CO? (A) Carbon has one fewer valence electron than nitrogen. (B) Carbon is less electronegative than nitrogen. (C) Carbon has a smaller atomic radius than nitrogen. (D) Carbon can form up to four bonds, while nitrogen can form only three.

The bond in gas-phase O2 (121 pm) is significantly longer than the bond in gas-phase O2+ (112 pm). What is the best explanation for this difference? (A) O2 has one more antibonding electron than O2+. (B) O2 has two unpaired electrons while O2+ has one. (C) The bond in O2 has less ionic character than the bond in O2+. (D) It requires more energy to remove an electron from O2 to form O2+ than it does to remove an electron from O to form O+.

The critical point of carbon dioxide is 304 K and 73 atm. Under which conditions is carbon dioxide a liquid? I. 303Kand73atm II. 305Kand74atm (A) I only (C) Both I and II (B) II only (D) Neither I nor II

The diagrams below represent the progress of a reaction of A → B, with molecules of A represented by solid circles and molecules of B represented by open circles. Which statement best describes the reaction at t = 1000 s? (A) The reaction is at equilibrium because the concentrations of A and B are no longer changing. (B) The reaction is not at equilibrium because not all of the A has been consumed. (C) The reaction is not at equilibrium because the concentrations of A and B are not equal. (D) The reaction is not at equilibrium because the positions of the molecules are still changing.

The following endothermic reaction is at equilibrium in a sealed container. PCl3(g) + Cl2(g)---><--- PCl5(g) Which of the following changes would result in an increase in the number of moles of PCl5(g) present at equilibrium? I. Increasing the temperature II. Increasing the volume A) I only (C) Both I and II (B) II only (D) Neither I nor II

The graph below shows the forward and reverse rates for a reaction as a function of time. At time t, a catalyst is added to the system, and the forward reaction rate is observed to change as indicated by the solid curve. Which dashed curve best indicates how the reverse reaction rate changes? (A) A (B) B (C) C (D) D

The molar mass of a volatile organic liquid is measured by weighing the mass of an empty flask of known volume, adding some of the liquid, heating the flask in a water bath until the liquid has just vaporized completely, then sealing the flask, letting it cool, and remeasuring the mass of the flask with the remaining organic compound. Which error will lead to a calculated value of the molar mass that is lower than the theoretical value? (A) The flask is not sealed promptly after the last of the compound vaporizes. (B) The organic compound dimerizes to an appreciable extent in the gas phase. (C) The barometric pressure was assumed to be 1 atm but in fact was greater than 1 atm. (D) The volume of the flask used in the calculation is smaller than the true volume.

The net chemical reaction of photosynthesis is best described as (A) an endothermic reaction that forms sugars. (B) an exothermic reaction that forms sugars. (C) an endothermic reaction that breaks down sugars. (D) an exothermic reaction that breaks down sugars.

The rate of a reaction is 2.3 times faster at 60 oC than it is at 50 oC. By what factor will the rate increase on going from 60 oC to 70 oC? (A) By less than a factor of 2.3 (B) By a factor of 2.3 (C) By more than a factor of 2.3 (D) The rate increase cannot be determined from the information given.

The reduction of O2 to H2O in acidic solution has a standard reduction potential of +1.23 V. What is the effect on the half-cell potential at 25 °C when the pH of the solution is increased by one unit? O2(g)+4H+(aq)+4e- 2H2O(l) (A) The half-cell potential decreases by 59 mV. (B) The half-cell potential increases by 59 mV. (C) The half-cell potential decreases by 236 mV. (D) The half-cell potential increases by 236 mV.

The sequence of amino acids in a protein is known as its (A) primary structure. (B) secondary structure. (C) tertiary structure. (D) quaternary structure.

The standard cell potential of the following galvanic cell is 1.562 V at 298 K. Zn(s) | Zn2+(aq) || Ag+(aq) | Ag(s) What is the cell potential of the following galvanic cell at 298 K? Zn(s) | Zn2+(aq, 1.00 × 10-3 M) || Ag+(aq, 0.150 M) | Ag(s) (A) 1.602 V (B) 1.626 V (C) 1.642 V (D) 1.691 V

The standard enthalpy of formation, ∆Hof, of the compound MgO(s) is equal to the standard enthalpy change for which reaction? (A) Mg(s) + 1⁄2 O2(g) MgO(s) (B) 2 Mg(s) + O2(g) 2 MgO(s) (C) Mg(g) + O(g) MgO(s) (D) Mg2+(aq) + O2-(aq) MgO(s)

The wavelength of one line in the emission spectrum of C is 538 nm. What is the energy of one photon with this wavelength? (A) 3.69 10-19 J (C) 3.56 10-40 J (B) 3.69 10-26 J (D) 1.19 10-48 J

Under what conditions will the behavior of a real gas best approximate the behavior of an ideal gas? I. High temperature II. High pressure (A) I only (C) Both I and II (B) II only (D) Neither I nor II

What are the units of k if the rate law of a reaction is rate = k[X]0[Y]0? (A) M s-1 (B) s-1 (C) M-1 s-1 (D) k is dimensionless

What is the average oxidation state of tungsten in sodium (A) +6.00 (B) +6.17 (C) +6.42 (D) +6.67

What is the concentration of H2O2 in a solution that is 30.0% by mass hydrogen peroxide and has a density of 1.11 g cm-3? (A) 9.79 M (C) 18.5 M (B) 12.6 M (D) 32.6 M

What is the concentration of a solution of K2CO3 that has pH = 11.90? (For H2CO3, Ka1 = 4.2 10-7, Ka2 = 4.8 10-11.) (A) 3.010-1 M (C) 7.910-3 M (B) 2.610-2 M (D) 1.310-12 M

What is the value of the quantum number l for a 5p orbital? (A) 1 (B) 2 (C) 3 (D) 4

What products are formed in the electrolysis of 1.0 M aqueous HBr? (A) H2 at the cathode, Br2 at the anode (B) O2 at the cathode, H2 at the anode (C) OH- at the cathode, HOBr at the anode (D) Br3- at the cathode, HBrO4 at the anode

What reaction conditions most effectively convert a carboxylic acid to a methyl ester? (A) CH3OH, HCl (B) CH3I, HCl (C) CH3OH, NaOH (D) CH3I, SOCl2

What state of matter corresponds to the diagram below? (A) Gas (C) Amorphous solid (B) Liquid (D) Crystalline solid

When 0.10 M solutions of ammonium acetate, barium acetate, and sodium acetate are ranked from least basic to most basic, what is the correct ordering? (A) NH4C2H3O2 < NaC2H3O2 < Ba(C2H3O2)2 (B) Ba(C2H3O2)2 < NH4C2H3O2 < NaC2H3O2 (C) NaC2H3O2 < Ba(C2H3O2)2 < NH4C2H3O2 (D) NaC2H3O2 < NH4C2H3O2 < Ba(C2H3O2)2

When 30.0 mL of 0.10 M AgNO3 is added to 30.0 mL of 0.10 M NaCl, aqueous NaNO3 and solid AgCl are formed. How much solid AgCl is produced? (A) 0.0030 mol (B) 0.0060 mol (C) 0.030 mol (D) 0.060 mol

Which aqueous solution exhibits the largest freezing point depression? (A) 1.0 m KBr (C) 0.5 m MgCl2 (B) 0.75 m C6H12O6 (D) 0.25 m Ga2(SO4)3

Which atom has the highest first ionization energy? (A) N (B) O (C) P (D) S

Which best describes the bonding in Cu(s)? (A) The copper atoms are positively charged in a sea of delocalized electrons. (B) The copper atoms are alternately positively and negatively charged. (C) The copper atoms form covalent bonds to adjacent copper atoms. (D) The copper atoms form hydrogen bonds to adjacent copper atoms.

Which compound has the highest normal boiling point? (A) 1-butanol, CH3CH2CH2CH2OH (B) 2-butanol, CH3CH2CH(CH3)OH (C) 2-methyl-1-propanol, (CH3)2CHCH2OH (D) 2-methyl-2-propanol, (CH3)3COH

Which compound is an ester?

Which compound reacts readily with Cr(VI) reagents?

Which compound will form the most intensely colored 0.01 M aqueous solution? (A) KMnO4 (C) KAl(SO4)2 (B) KClO4 (D) KI

Which electronic transition in atomic hydrogen corresponds to the emission of visible light? (A) n=5--->n=2 (B) n=1--->n=2 (C) n=3--->n=4 (D) n=3--->n=1

Which molecule has a trigonal pyramidal geometry? (A) PCl3 (B) BCl3 (C) IF3 (D) SO3

Which molecule is nonpolar, yet contains polar covalent bonds? (A) CO2 (B) HCN (C) NH3 (D) P4

Which of the following reactions takes place with an increase in entropy under standard conditions? (A) NH4+(aq) + CH3COO-(aq) NH3(aq) + CH3COOH(aq) (B) CaO(s) + CO2(g) CaCO3(s) (C) NH3(g) + HCl(g) NH4+(aq) + Cl-(aq) (D) C2H4(g) + Br2(l) C2H4Br2(l)

Which of the following statements is best supported by the data from Rutherford's experiment of scattering alpha particles with a thin metal foil? (A) The mass and positive charge of an atom are concentrated in its center. (B) Electrons in atoms occupy only certain specific energy levels. (C) Moving particles can also be described as waves. (D) Atoms of a given element do not all have identical masses.

Which of the following would lead to an increase in the vapor pressure of a liquid? I. Increasing the temperature (A) I only II. Adding a nonvolatile solute (A) I only (B) II only

Which set of quantum numbers n, l, ml, ms is invalid? (A) 1,1,0,-1⁄2 (B) 2,0,0,+1⁄2 (C) 3,1,0,+1⁄2 (D) 4,3,2,-1⁄2

Which solid is least soluble in water at 298 K? (A) CaF2 (B) AgF. (C)Ba(OH)2 (D) CoSO4

Which solution has the greatest percent ionization? (A) 0.010 M formic acid (Ka = 1.8 10-4) (B) 0.10 M formic acid (Ka = 1.8 10-4) (C) 0.010 M acetic acid (Ka = 1.8 10-5) (D) 0.10 M acetic acid (Ka = 1.8 10-5)

Which statement about bonding is correct? (A) A bond has cylindrical symmetry about the bonding axis. (B) A π bond is twice as strong as a bond. (C) A double bond consists of two π bonds. (D) A π bond results from the sideways overlap of hybridized orbitals.

Which statement regarding the relative energies of monochromatic light with λ = 800 nm and monochromatic light with λ = 400 nm is correct? (A) 800 nm light has half as much energy per mole of photons as 400 nm light. (B) 800 nm light has the same energy per mole of photons as 400 nm light. (C) 800 nm light has twice as much energy per mole of photons as 400 nm light. (D) No conclusion may be drawn regarding the relative energy per mole of photons without knowing the intensity of the light.

Which two bases are found as a hydrogen-bonded base pair in DNA? (A) A and T (B) C and T (C) C and U (D) G and U

Which would be most suitable for measuring 2.7 mL of ethanol for addition to a reaction with acidified dichromate? (A) 10-mL graduated cylinder (B) 10-mL volumetric flask (C) 10-mL volumetric pipet (D) 10-mL beaker

20 mL of an approximately 10% aqueous solution of ethylamine, CH3CH2NH2, is titrated with 0.3000 M aqueous HCl. Which indicator would be most suitable for this titration? The pKa of CH3CH2NH3+ is 10.75. (A) Thymol blue, color change from pH = 1.2 to 2.8 (B) Bromocresol green, color change from pH = 4.0 to 5.6 (C) Phenolphthalein, color change from pH = 8.0 to 10.0 (D) Alizarin yellow R, color change from pH = 10.0 to 12.0

A 1.0 M aqueous solution of which compound has the lowest pH? (A) CH3CH2OH (B) CH3COOH (C) CH3CHO (D) Cl3CCHO

A 10.00 g sample of a compound containing only carbon, hydrogen, and oxygen forms 23.98 g CO2 and 4.91 g H2O upon complete combustion. What is the empirical formula of the compound? (A) C2HO (B) C3H3O (C) C6H3O2 (D) C6H6O

A 2.0 mL sample of a colorless solution, when treated with a few drops of 2 M hydrochloric acid, forms a white precipitate which dissolves when the solution is heated to boiling. The original solution could have contained which of the following cations? I. 0.1 M Ag+ II. 0.1 M Pb2+ (A) I only (B) II only

A 25.0 mL sample of 0.15 M silver nitrate, AgNO3, is reacted with a 3.58 g sample of calcium chloride, CaCl2 (M = 111.0). Which of the following statements is true? (A) Silver nitrate is the limiting reactant and calcium nitrate precipitates. (B) Silver nitrate is the limiting reactant and silver chloride precipitates. (C) Calcium chloride is the limiting reactant and calcium nitrate precipitates. (D) Calcium chloride is the limiting reactant and silver chloride precipitates.

A 5.00 g mixture of potassium sulfide and potassium chloride contains 2.80 g potassium. What percentage by mass of the mixture is potassium sulfide? (A) 13.8% (B) 19.2% (C) 44.0% (D) 96.1%

A sample of methanol, CH3OH, is introduced into an evacuated chamber with a movable piston. The pressure is measured as a function of the volume of the container while the temperature is maintained at 50 oC, and the graph below is obtained. Which statements are correct? I. At volumes less than 60 mL, only liquid methanol is present. II. At volumes greater than 60 mL, only gaseous methanol is present. (A) I only (C) Both I and II (B) II only (D) Neither I nor II

A sample of neon gas is held at 25.0 oC and 1.0 atm in a cylinder with a movable piston. Under these conditions the gas occupies 5.0 L. What volume does the gas occupy at 12.5 oC and 1.0 atm? (A) 2.5L (B) 4.8L (C) 5.2L (D) 10L

A solution contains 0.1 M Sr2+ ions and 0.1 M Ag+ ions. Addition of an equal volume of a 0.5 M solution of which reagent will cause precipitation of a strontium salt but not a silver salt? (A) NaNO3 (C) NaOH (B) NaF (D) NaCl

A strip of metallic zinc is placed in a beaker containing dilute aqueous copper(II) nitrate. Which statement correctly describes what takes place? (A) No reaction takes place. (B) The mass of the metal strip decreases as the zinc is oxidized. (C) A white precipitate of CuNO3 is formed. (D) Bubbles of NO(g) form as the nitrate ion is reduced.

A student is separating CHCl3 (bp = 61 °C) from CHCl2CHCl2 (bp = 146 °C) by distillation. She has just begun to collect the first distillate in the receiving flask. At what position in the apparatus will the temperature be 61 °C? (A) A (B) B

A two-dimensional slice through the lattice of a crystalline solid containing two different elements X and Y is shown schematically and to scale below. What type of solid is it? (A) A metallic alloy such as FeCr (B) A molecular solid such as IBr (C) An ionic compound such as LiCl (D) A network covalent solid such as SiC

A60.0gsampleofCaCO3 isheatedto950Kina1.00L evacuated container, where it reacts according to the following equation: CaCO3(s) CaO(s) + CO2(g) After equilibrium is attained, the pressure of CO2(g) is 30.0 mm Hg. When the experiment is repeated using 120.0 g CaCO3, what is the equilibrium pressure P? (A) 15.0mmHg≤P<30.0mmHg (B) P=30.0mmHg (C) 30.0mmHg<P<60.0mmHg (D) P=60.0mmHg

Consider the four gases CO2, N2, CCl4, and He. Which is the correct order of increasing average molecular speed at 100 oC? (A) He<N2 <CO2 <CCl4 (B) CCl4 <CO2 <N2 <He (C) He<CO2 <N2 <CCl4 (D) CCl4 <N2 <CO2 <He

Copper(I) oxide, Cu2O, is reduced to metallic copper by heating in a stream of hydrogen gas. What mass of water is produced when 10.00 g copper is formed? (A) 1.259 g (B) 1.417 g (C) 2.835 g (D) 5.670 g

Electrolysis of water containing sulfuric acid as an electrolyte is carried out as shown and the gases produced at the electrodes collected in two identical tubes, both initially filled with the sulfuric acid solution. After electrolysis has been carried out for a certain time, which picture best represents the appearance of the tubes?

For a constant-pressure process, what is the difference between the internal energy change (∆U) and the enthalpy change (∆H)? (A) Heat (C) Entropy (B) Work (D) Gibbs free energy

For an exothermic reaction, which of the following best describes the effect of increasing the temperature on the forward and reverse reactions? (A) Both the forward and reverse rates increase, but the forward rate increases more than the reverse rate. (B) Both the forward and reverse rates increase, but the reverse rate increases more than the forward rate. (C) The forward rate increases while the reverse rate decreases. (D) The reverse rate increases while the forward rate decreases.

For the reaction Cl2(aq) + 2 Br-(aq) Br2(aq) + 2 Cl-(aq) which of the following could be used to monitor the rate? I. pH meter II. Spectrophotometer (A) I only (B) II only

For the reaction: Cr(H2O)63+(aq) + SCN-(aq) Cr(H2O)5SCN2+(aq) + H2O(l) The following data were collected: What is the rate law for the reaction? (A) Rate = (9.1 10-9 M-1 hr-1)[Cr(H2O)63+][SCN-] (B) Rate = (7.2 10-3 M-1 hr-1)[Cr(H2O)63+][SCN-] (C) Rate = (2.9 10-4 hr-1)[Cr(H2O) 63+] (D) Rate = (3.9 10-4 hr-1)[Cr(H2O)63+]

Given the enthalpy changes: A + B CA + D E + F F C + E ∆H = -35 kJ•mol-1 ∆H = +20 kJ•mol-1 ∆H = +15 kJ•mol-1 What is ∆H for the reaction 2A + B + D → 2 F? (A) 0 kJ•mol-1 (B) -30 kJ•mol-1 (C) -40 kJ•mol-1 (D) -70 kJ•mol-1

Given the standard enthalpy changes for the reactions: P4(s) + 3 O2(g) P4O6(s) ΔHo = -1640 kJ mol-1 P4(s) + 5 O2(g) P4O10(s) ΔHo = -2940 kJ mol-1 Calculate the standard enthalpy change ∆Ho for the following reaction: P4O6(s) + 2 O2(g) P4O10(s) (A) -4.58 103 kJ mol-1 (B) -1.30 103 kJ mol-1 (C) 1.79 kJ mol-1 (D) 4.82 106 kJ mol-1

How many stereoisomers does the square planar complex Pt(NH3)2(Br)(Cl) have? (A) One (B) Two (C) Three (D) Four

If the average carbon-hydrogen bond dissociation enthalpy in ethane is 416 kJ mol-1, what is the bond dissociation enthalpy of the carbon-carbon bond in ethane? (A) 164 kJ mol-1 (C) 386 kJ mol-1 (B) 333 kJ mol-1 (D) 404 kJ mol-1

In a galvanic cell in which the following spontaneous reaction takes place, what process occurs at the cathode? 3 Ce4+(aq) + Cr(s) 3 Ce3+(aq) + Cr3+(aq) (A) Reduction of Cr3+(aq) (B) Reduction of Ce4+(aq) (C) Oxidation of Cr(s) (D) Oxidation of Ce3+(aq)

In which of the following substances is chlorine in the lowest oxidation state? (A) Cl2 (B) KCl (C) KClO (D) KClO4

One unit cell of a crystal containing elements X, Y, and Z is shown below. What is its formula? (A) XYZ (B) XYZ3 (C) XY4Z2 (D) XY8Z6

Sulfuryl chloride (SO2Cl2) decomposes via first-order kinetics. The half-life is 4.1 minutes at a certain temperature. How long does it take for 30% of the SO2Cl2 in a sample to decompose at this temperature? (A) 0.6 min. (B) 2.1 min (C) 2.5 min (D) 7.1 min

Tert-butyl alcohol reacts with aqueous hydrochloric acid to give tert-butyl chloride. (CH3)3COH(aq) + H+(aq) + Cl-(aq) → (CH3)3CCl(aq) + H2O(l) For this reaction, Rate = k[(CH3)3COH][H+]. With which mechanism is this rate law consistent? (A) (CH3)3COH(aq) + H+(aq) ---><---- (CH3)3C(OH2)+(aq). fast (CH3)3C(OH2)+(aq) + Cl-(aq) → (CH3)3CCl(aq) + H2O(l). slow (B) (CH3)3COH(aq) + H+(aq) ---><---- (CH3)3C(OH2)+(aq)---> fast (CH3)3C(OH2)+(aq) (CH3)3C(OH2)+(aq) → (CH3)3C+(aq) + H2O(l) slow (CH3)3C+(aq) + Cl-(aq) → (CH3)3CCl(aq) fast (C) (CH3)3COH(aq) + Cl-(aq) → (CH3)3CCl(aq) + OH-(aq) slow OH-(aq) + H+(aq) → H2O(l) fast (D) (CH3)3COH(aq) → (CH3)3C+(aq) + OH-(aq) slow (CH3)3C+(aq) + Cl-(aq) → (CH3)3CCl(aq) fast OH-(aq) + H+(aq) → H2O(l) fast

The acidity of the group 16 hydrides increase going down the group (H2O << H2S < H2Se < H2Te). Which is the best explanation for this trend? (A) The electronegativity of the group 16 elements increases going down the group. (B) The polarizability of the group 16 elements increases going down the group. (C) The polarity of the X-H bond increases going down the group. (D) The H-X-H bond angle increases going down the group.

The bond in F2 has a smaller bond dissociation enthalpy than the bond in Cl2. Which is the best explanation for this difference? (A) Fluorine is more electronegative than chlorine. (B) Lone pair-lone pair repulsions are stronger in F2 than in Cl2. (C) The F-F bond is longer than the Cl-Cl bond. (D) Chlorine has energetically accessible d orbitals while fluorine does not.

The concentration of sulfate ion in a solution is measured by precipitating the sulfate as BaSO4, filtering the precipitate on ashless filter paper, and heating the filter paper and precipitate in a tared crucible with a Bunsen burner. Which error will result in a sulfate concentration that is higher than the actual concentration? (A) The empty crucible contains a few drops of water when it is tared. (B) A glass fiber filter is used instead of ashless filter paper. (C) Some fine precipitate is not captured by the filter. (D) Some of the sulfate-containing solution spills before the BaCl2 solution is added.

The cubic unit cell of a perovskite structure containing atoms of types A, B, and C is illustrated below. What is the empirical formula of this substance? (A) ABC (B) ABC3 (C) AB4C6 (D) AB8C12

The endothermic reaction shown below is at equilibrium in a sealed flask, with significant amounts of both Ca(OH)2(s) and CaO(s) present. Which action will increase the amount of Ca(OH)2(s) at equilibrium? Ca(OH)2(s) CaO(s) + H2O(g) ∆H° > 0 (A) Crushing the Ca(OH)2(s) into smaller pieces (B) Decreasing the temperature of the flask (C) Adding more CaO(s) to the flask (D) Adding N2(g) to the flask

The enthalpy change under standard conditions for which of the reactions below would be equal to the ∆H°f of NaOH(s)? (A) Na(s) + H2O(l) NaOH(s) + 1/2 H2(g) (B) Na(s) + 1/2 O2(g) + 1/2 H2(g) NaOH(s) (C) Na(s) + 1/2 H2O2(l) NaOH(s) (D) Na+(aq) + OH-(aq) NaOH(s)

The formation of NOBr, 2 NO(g) + Br2(g) → 2 NOBr(g),is studied, and the following mechanism is proposed: NO(g) + Br2(g) NOBr2(g) fast, equilibrium NO(g) + NOBr2(g) → 2 NOBr(g) slow What rate law is predicted by this mechanism?(A) Rate = k[NO][Br2] (B) Rate = k[NO]2[Br2] (C) Rate = k[NO][Br2]2 (D) Rate = k[NO]2 (A) Rate = k[NO][Br2] (B) Rate = k[NO]2[Br2] (C) Rate = k[NO][Br2]2 (D) Rate = k[NO]2

The mineral crocidolite has the formula formula unit are in the +2 oxidation state and how many are in the +3 oxidation state? (A) All five are +2 (B) Three are +2, two are +3 (C) Two are +2, three are +3 (D) One is +2, four are +3

The molar mass of a solid carboxylic acid is determined by titrating a known mass of the acid with a standardized solution of NaOH to a phenolphthalein endpoint. Which errors will lead to a molar mass that is smaller than the actual molar mass? I. Some of the acid is spilled when being transferred into the titration flask. II.The endpoint is recorded when the solution is dark red in color rather than light pink. (A) I only (C) Both I and II (B) II only (D) Neither I nor II

The normal boiling points of molecular fluorine, chlorine, bromine, and iodine increase in that order. Which of the following statements accounts for this increase? (A) The chemical reactivity decreases in that order. (B) The London dispersion forces increase in that order. (C) The dipole-dipole forces increase in that order. (D) The hydrogen bonding increases in that order.

The peroxymonosulfate anion, HSO5-, has (A) five sulfur-oxygen bonds and no oxygen-oxygen bonds. (B) four sulfur-oxygen bonds and one oxygen-oxygen bond. (C) three sulfur-oxygen bonds and two oxygen-oxygen bonds. (D) one sulfur-oxygen bond and four oxygen-oxygen bonds.

The rate of decomposition of hydrogen peroxide is first order in H2O2. At [H2O2] = 0.150 M, the decomposition rate was measured to be 4.83 × 10-6 M•s-1. What is the rate constant for the reaction? (A) 2.15×10-4 s-1 B) 3.22×10-5 s-1 (C) 4.83 × 10-6 s-1 D) 7.25 × 10-7 s-1

The specific heat capacity of iron is 0.461 J g-1 K-1 and that of titanium is 0.544 J g-1 K-1. A sample consisting of a mixture of 10.0 g Fe and 10.0 g Ti at 100.0 oC loses 200. J of heat to the environment. What is the final temperature of the sample? (A) 89.9 oC (B) 80.1 oC (C) 60.2 oC (D) 39.8 oC

The standard enthalpy of formation, ∆Hof, for HCOOH(l) is equal to the standard enthalpy change for which reaction? (A) C(g) + 2 H(g) + 2 O(g) HCOOH(l) (B) C(s) + H2(g) + O2(g) HCOOH(l) (C) C(g) + H2(g) + O2(g) HCOOH(l) (D) CO2(g) + H2(g) HCOOH(l)

The standard enthalpy of reaction for the dissolution of silica in aqueous HF is 4.6 kJ mol-1. What is the standard enthalpy of formation of SiF4(g)? SiO2(s) + 4 HF(aq) → SiF4(g) + 2 H2O(l) ∆Horxn = 4.6 kJ mol-1 (A) -1624.3 kJ mol-1 (C) -949.8 kJ mol-1 (B) -1615.1 kJ mol-1 (D) -940.6 kJ mol-1

The tetragonal unit cell of white tin is shown below. Each circle represents a tin atom, with the gray circles sitting on the four vertical faces of the unit cell. How many tin atoms are contained in this unit cell? (A)2 (B)4 (C)8 (D)13

What is Eo for the following reaction? 2 Al3+(aq) + 3 Zn(s) 2 Al(s) + 3 Zn2+(aq) (B) -0.90 V

What is the change in standard free energy at 298 K for the conversion of ozone to molecular oxygen as shown in the equation below? 2 O3(g) → 3 O2(g) ∆G° = ??? (A) -164 kJ mol-1 (C) -401 kJ mol-1 (B)-328 kJ mol-1 (D)-492 kJ mol-1

What is the equilibrium constant for the following reaction at 25 °C? 2 Ag+(aq) + Cu(s) → Cu2+(aq) + 2 Ag(s) (B)3.6 1015

What is the formal charge on the central nitrogen in the Lewis structure of N2O? (A) 0 (B) +1 (C) -1 (D) 0 in some resonance structures, -1 in other resonance structures

What is the geometry of the chlorate ion, ClO3-? (A) trigonal planar (B) trigonal pyramidal (C) T-shaped (D) zigzag

What is the nature of the peptide bonds in a protein? (A) Hydrogen bonds (B) Amide bonds (C) Disulfide bonds (D) Ionic bonds

What is the oxidation number of C in formaldehyde, CH2O? (A) -2 (B) 0 (C) +2 (D) +4

What is the pH of a 0.20 M solution of sodium benzoate, Na(C6H5COO)? The Ka of benzoic acid, C6H5COOH, is 6.5 10-5. (A) 5.26 (B) 8.74 (C) 9.09 (D) 11.56

What is the product of alpha emission from the isotope uranium-238? (A) 232Th (B) 234Th (C) 237Np (D) 231Pa

What is the standard Gibbs free energy of formation, ∆Gof, of NH3(g) at 298 K? (A) -104 kJ mol-1 (B) -16 (C) -7 kJ mol-1 (D) 13

What is the structure of polypropylene, formed by the polymerization of propene (CH2=CHCH3)?

What mass of silver chloride (M = 143.4) will dissolve in 1.00 L of water? The Ksp of AgCl is 1.8 × 10-10. (A) 1.4mg (B) 1.9mg (C) 2.9mg

What mode of radioactive decay does 66Cu undergo? (A) Alpha decay (C) Electron capture (B) Beta decay (D) Positron emission

When an aqueous solution of KI is electrolyzed, what forms at the anode? (A) O2 (B) I2 C) K D) H2O

When the equation ClO2(aq) + OH-(aq) ClO2-(aq) + ClO3-(aq) + H2O(l) is balanced, what is the ratio of the coefficient of ClO2 to that of ClO3-? (A) 1 : 1 (B) 2 : 1 (C) 3 : 1 (D) 3 : 2

Which aqueous solution has the highest boiling point? (A) 1.0 m acetic acid, CH3COOH (B) 1.0 m sulfuric acid, H2SO4 (C) 1.0 m phosphoric acid, H3PO4 (D) 1.0 m glucose, C6H12O6

Which combination of dilute aqueous reagents will not produce a precipitate? (A) AgNO3 + HCl (B) NaOH + HClO4 (C) BaBr2 + Na2SO4 (D) ZnI2 + KOH

Which compound can exhibit geometric isomerism? (A) 1-butene (B) 2-butene (C) 1-butyne (D) 2-butyne

Which compound has the lowest normal boiling point? (A) HF (B) HCl (C) HBr (D) HI

Which compound is NOT considered aromatic?

Which contains sp3-hybridized carbon atoms? (A) Benzene, C6H6 (B) Ethane, C2H6 (C) Ethene, C2H4 (D) Ethyne, C2H2

Which gas-phase atom has no unpaired electrons in its ground state? (A) Li (B) Be (C) B (D) C

Which gas-phase atoms in their ground states are diamagnetic? I. Fe II. Zn (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Which gas-phase molecule is NOT linear? (A) CS2 (B) SO2 (C) HCCH (D) BrCN

Which halogen atom has the greatest electron affinity? (A) F (B) Cl (C) Br (D) I

Which is not a stable molecule? (A) NF3 (B) NF5 (C)PF3 (D) PF5

Which molecule has a dipole moment of zero? (A) CO (B) CO2 (C) CH2O (D) CH3OH

Which molecule is planar? (A) CF4 (B) COF2 (C) SF4 (D) SOF2

Which of the following combinations will produce a 0.4 M NaCl solution? (A) Mixing 500 mL of 0.4 M NaOH with 500 mL of 0.4 M HCl (B) Mixing 300 mL of 1.2 M NaOH with 600 mL of 0.6 M HCl (C) Mixing 500 mL of 0.4 M NaCl solution with 500 mL water (D) Diluting 400 mL of 0.6 M NaCl with water to a final volume of 1.0 L

Which of the following gas-phase ions has the largest number of unpaired electrons in its ground state? (A) Cr3+ (B) Co3+ (C) Ni2+ (D) Cu2+

Which of the following is NOT classified as a biopolymer? (A) Collagen (B) Glucose (C) Cellulose (D) Chitin

Which of the following is a mathematical statement of the first law of thermodynamics? (A) ∆V=(nR/P)∆T (C) ∆H=∆E+P∆V (B) ∆E=q+w (D) ∆G=∆H-T∆S

Which of the following will increase [Cl-] in a saturated solution of AgCl in contact with excess solid silver chloride? I. Addition of AgCl(s) II. Addition of NH3(aq) (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Which reaction would yield a single alkene product?

Which set of quantum numbers could NOT correspond to an electron in a ground-state gas phase Pd atom? (A) n=2,l=1,ml =-1,ms =1/2 (B) n=3,l=3,ml =-1,ms =-1/2 (C) n=4,l=0,ml =0,ms =-1/2 (D) n=4,l=2,ml =2,ms =1/2

Which statement about unsaturated fats is NOT correct? (A) Unsaturated fats contain carbon-carbon double bonds. (B) Unsaturated fats generally have higher melting points than saturated fats with the same number of carbon atoms. (C) Unsaturated fats can be converted to saturated fats by treatment with H2 in the presence of a metal catalyst. (D) Unsaturated fats must contain oxygen.

Which structure best represents the sulfur-containing species produced in the reaction of (CH3)2S with CH3I?

40.0 mL of 0.200 M aqueous NaOH is added to 200.0 mL of 0.100 M aqueous NaHCO3 in a flask maintained at 25 oC. Neglecting the effects of dilution, what is q for this reaction? (C) -330 J

52Mn undergoes radioactive decay to give 52Cr by what decay mode? (A) Alpha emission (B) Beta emission (C) Positron emission (D) Gamma emission

A 0.100 M aqueous solution of H2SeO3 is titrated with 1.000 M NaOH solution. At the point marked with a circle on the titration curve, which species represent at least 10% of the total selenium in solution? (A) H2SeO3 only (C) HSeO3- only (B) Both H2SeO3 and HSeO3- (D) Both HSeO3- and SeO32-

A 0.12 M solution of a monoprotic acid is 2.3% ionized. What is the Ka of this acid? (A) 2.8 10-3 (C) 6.5 10-5 (B) 3.3 10-4 (D) 7.6 10-6

A 1.00 g sample of a hydrogen peroxide (H2O2) solution is placed in an Erlenmeyer flask and diluted with 20 mL of 1 M aqueous sulfuric acid. To this solution is added 0.0200 M KMnO4 solution via a buret, until a pale purple color persists. This requires 22.50 mL of KMnO4 solution. What is the percent by mass of hydrogen peroxide in the original solution? (A) 0.613% (B) 1.53% (C) 3.83% (D) 7.65%

A 3.0 L sample of helium gas is stored in a rigid, sealedcontainer at 25 °C and 1.0 atm pressure. The temperature is increased to 125 °C. What is the new pressure of the gas? (A) 0.20 atm (B) 0.75 atm (C) 1.3 atm (D) 5.0 atm

A current of 0.15 A is passed through an aqueous solution of K2PtCl4. How long will it take to deposit 1.00 g Pt(s) (M = 195.1)? (A) 1600 s (B) 3300 s (C) 6600 s (D) 13000 s

A portion of the phase diagram of elemental sulfur is shown below. Which statement about sulfur is correct? A)Rhombic sulfur cannot be sublimed without first converting to monoclinic sulfur B)The conversion of rhombic sulfur to monoclinic sulfur is exothermic. C)Rhombic sulfur is denser than monoclinic sulfur. D)At atmospheric pressure, monoclinic sulfur cannot be in equilibrium with liquid sulfur

A portion of the phase diagram of uranium hexafluoride (UF6) is shown below. Which statements are correct? I. UF6 sublimes at atmospheric pressure. II. At 80 oC and 1.5 atm, only UF6(g) is present at equilibrium A) I ONLY (B) II ONLY (C) BOTH I AND II (D) NEITHER I OR II

A reaction has Keq = 20 at 298 K, and Keq increases with increasing temperature between 298 K and 350 K. What may be concluded from these observations? I. ∆G°rxn <0at330K II. ∆S°rxn > 0 at 330 K (A) I only (B) II only (C) Both I and II (D) Neither I nor II

A sample of 54.0 g of methanol is heated from 25.0 °C to 35.0 °C. How much heat is required? The specific heat capacity of methanol is 2.48 J g-1 K-1. (A) 0.00459 J (B) 0.0747 J (C) 1340 J ( D) 4690 J

A solid has a melting point of 1710 °C, is soluble in water, and does not conduct electricity in the solid state. What is the most likely nature of the bonding in this solid? (A) Molecular covalent (C) Ionic (B) Network covalent (D) Metallic

A solution of which compound gives a violet flame test? (A) LiBr (B) NaCl (C) KNO3 (D) B(OH)3

A student is using a buret for a titration. What initial buret reading should be recorded? (A) 6.6 mL (C) 6.63 mL (B) 7.4 mL (D) 7.37 mL

A vessel contains 66 g CO2 and 16 g O2 at a pressure of 10.0 atm. What is the partial pressure of CO2? (A) 5.0 atm (B) 6.0 atm (C) 7.5 atm (D) 8.0 atm

A white ionic solid is dissolved in water. Addition of a solution of sodium chloride to this solution results in a white precipitate. What was the cation in the original ionic solid? (A) Na+ (B) Fe3+ (C) Ag+ (D) Sr2+

An orbital in a ground-state gas-phase As atom has n = 3, l = 1. How many electrons are in this orbital? (A)0 (B)1 (C)2 (D)6

At equilibrium, a solution contains 0.50 mol each of Cd2+(aq), SCN-(aq), and Cd(SCN)42-(aq). What is the solution's volume? Cd2+(aq) + 4 SCN-(aq) =Cd(SCN)42-(aq) Kf =1.0×103 (A) 2.0L (B) 2.2L (C) 2.8L (D) 8.0L

Atoms of which element have the smallest ionization energy? (A) Na (B) F (C) K (D) Cl

Calcium oxalate, CaC2O4 (M = 128.1), dissolves to the extent of 0.67 mg L-1. What is its Ksp? (A) 6.7 10-4 (B) 4.5 10-7 (C) 2.7 10-11 (D) 5.7 10-16

Copper electrodes are placed into two aqueous solutions of copper(II) sulfate at 25 oC. One compartment contains a 1.0 M solution while the other compartment contains a 0.10 M solution. The two compartments are connected with a salt bridge and the electrodes are connected by a wire passing through a voltmeter. In what direction do the electrons flow through the wire, and what is the cell potential read on the voltmeter? (A) From the electrode in the 1.0 M solution to the electrode in the 0.10 M solution 30 mv B) From the electrode in the 1.0 M solution to the electrode in the 0.10 M solution 59 mv (C) From the electrode in the 0.10 M solution to the electrode in the 1.0 M solution 30 mv (D) From the electrode in the 0.10 M solution to the electrode in the 1.0 M solution 59 mv

Copper(II) hydroxide, Cu(OH)2, has Ksp = 2.2 10-20. For the reaction below, Keq = 4.0 10-7. What is Kf for Cu(NH3)42+? Cu(OH)2(s) + 4 NH3(aq)---><---Cu(NH3)42+(aq) + 2 OH-(aq) (A) 8.8 10-27 (C) 1.8 1013 (B) 5.5 10-14 (D) 1.1 1026

For an irreversible reaction A products, the graph of 1/[A] as a function of time is linear. What is the reaction order in A? (A) Zeroth-order (B) First-order (C) Second-order (D) The order in A cannot be determined based on the information given.

For the reaction 5O2(g) + 4NH3(g) 4NO(g) + 6H2O(g) if NH3 is being consumed at a rate of 0.50 M•s-1, at what rate is H2O being formed? (A) 0.33 M•s-1 (B) 0.50 M•s-1 (C) 0.75 M•s-1 (D) 3.0 M•s-1

Given the two standard reduction potentials below, what is the Ksp of Ag2CrO4 at 25 °C? Ag2CrO4(s) + 2 e- 2 Ag(s) + CrO42-(aq) Eo = +0.446 V Ag+(aq) + e- Ag(s) Eo = +0.799 V (A) 8.64 1011 (B) 1.08 10-6 (C) 1.16 10-12 (D) 1.11 10-39

How many and π bonds are in 1,3-butadiene, H2C=CH-CH=CH2? (A) 7and2bonds (C) 9and2bonds (B) 2and7bonds (D) 2and9bonds

How many distinct compounds have the formula C5H12? (A) One (B) Two (C) Three (D) Four

How many isomers have the formula C2H2Br2? (A) 1 (B) 2 (C) 3 (D) 4

How many oxygen atoms are in 225 g O2? (A) 4.23 1024 (B) 6.84 1024 (C) 8.47 1024 (D) 1.69 1025

How many sigma bonds are in 2-butyne (CH3CCCH3)? (A) 3 (B) 6 (C) 9 (D) 11

How many π bonds are in a molecule of propyne, C3H4? (A) 0 (B) 1 (C) 2 (D) 3

How many σ bonds and how many π bonds are present in allene, H2CCCH2? (A) One σ, one π (B) Five σ, one π (C) Six σ ,two π (D) Seven σ ,two π

IBr(g) is in equilibrium with I2(g) and Br2(g) at 150 oC: 2 IBr(g) I2(g) + Br2(g) K = 8.50 10-3 Initially, a closed vessel at 150 oC has a partial pressure of IBr of 0.350 atm and partial pressures of I2 and Br2 each of 0.750 atm. What is the partial pressure of IBr once the system reaches equilibrium? (A) 1.01 atm (B) 1.09 atm (C) 1.56 atm (D) 1.82 atm

In a study of the reaction below, the concentration of O2(g) is found to be decreasing by 0.042 M min-1.At what rate is the concentration of nitrogen dioxide gas changing? 2 NO(g) + O2(g) → 2 NO2(g) (A) Increasing by 0.021 M min-1 (B) Increasing by 0.042 M min-1 (C) Increasing by 0.084 M min-1 (D) It cannot be determined without knowing the rate law for the reaction.

In the reaction A B, a plot of 1/[A] vs. t is found to be linear. What is the reaction order in A? (A) Zeroth order (C) Second order (B) First order (D) Third order

In which of the following ways may a catalyst increase the rate of a reaction? I. It may alter the rate law. II. It may decrease the overall activation energy. (A) I only (B) II only (C) Both I and II (D) Neither I nor II

Iodine-131 decays with a half-life of 8.02 d. In a sample initially containing 5.00 mg of 131I, what mass remains after 6.01 d? (A) 1.13 mg (C) 2.97 mg (B) 1.87 mg (D) 3.13 mg

Methanol is produced industrially by catalytic hydrogenation of carbon monoxide according to the following equation: CO(g) + 2 H2(g) → CH3OH(l) If the yield of the reaction is 40%, what volume of CO (measured at STP) would be needed to produce 1.0 × 106 kg CH3OH? (A) 2.8×108 L (C) 1.7×109 L (B) 7.0×108 L (D) 2.1×109 L

Molecules from which class of biopolymers can react with water, in the presence of suitable enzymes, to form smaller examples of that class of biopolymers? I. Proteins II. Polysaccharides (A) I only (C) Both I and II (B) II only (D) Neither I nor II

N2 is a stable molecule and the N4 molecule is unknown. P4 is much more stable than molecular P2. Which is the best explanation for this difference? (A) N2 has valence electrons only in bonding and nonbonding orbitals, while P2 has some valence electrons in antibonding orbitals. (B) The greater electronegativity of N compared to P stabilizes compounds with lower molar masses. (C) The greater size of P compared to N results in decreased overlap in pi bonds. (D) The preference of P to adopt smaller bond angles than N favors formation of tetrahedral P4 molecules.

Nitrogen has a greater first ionization energy than oxygen. What is the best explanation for this observation? (A) Nitrogen is more electronegative than oxygen. (B) A nitrogen atom is smaller than an oxygen atom. (C) The electron ionized from nitrogen experiences less electron-electron repulsion than the electron ionized from oxygen. (D) The electron ionized from nitrogen is a 2s electron, while the electron ionized from oxygen is a 2p electron.

One hydrogen in 1-butene is replaced by bromine to give a chiral molecule. Which hydrogen is replaced? (A) HA (B) HB (C) HC (D) HD

Phosphorus acid, H3PO3, is a diprotic acid in aqueous solution (pK1 = 2.0, pK2 = 6.6). Which Lewis structure best represents HPO32-?

The half-life of iodine-131 is 8.02 days. How long will it take for 80.% of the sample to decay? (A) 2.6 days (C) 19 days (B) 13 days (D) 32 days

The lattice energy (energy required to separate the ions in an ionic solid) of MgO is much larger than that of LiF. What contributes the most to this difference? (A) Mg2+ is a smaller ion than Li+, and O2- is a smaller ion than F-. (B) F is more electronegative than O, and Li is more electropositive than Mg. (C) MgO contains doubly charged ions, while LiF contains singly charged ions. (D) MgO contains more electrons than LiF.

The mineral enargite is 48.41% Cu, 19.02% As, and 32.57% S by mass. What is the empirical formula of enargite? (A) CuAsS (C) Cu3AsS4 (B) Cu2AsS2 (D) Cu4AsS3

The nitrite ion, NO2-, can be represented as a resonance hybrid of two significant Lewis structures. Which statements about this are correct? I. The two resonance structures contribute equally to the structure. II. The formal charge of nitrogen is zero in both resonance structures. (A) I only (C) Both I and II (B) II only (D) Neither I nor II

The rate constant of a chemical reaction increases 26% when the temperature is raised from 50 oC to 55 oC. What is the activation energy of this reaction? (A) 1.1 kJ mol-1 (C) 41 kJ mol-1 (B) 18 kJ mol-1 (D) 220 kJ mol-1

The vaporization of a liquid at a certain temperature and pressure is spontaneous. For this process, which of the inequalities regarding the Gibbs free energy G and the internal energy E are correct? I. ∆G<0 II. ∆E<∆H (A) I only (C) Both I and II (B) II only (D) Neither I nor II

Toluene, C7H8, has both a higher vapor pressure than water at 25 oC and a higher normal boiling point. Which statement best explains these observations? (A) Liquids with higher vapor pressures typically have higher boiling points. (B) Toluene has a higher molar mass than water. (C) Toluene has a lower heat of vaporization than water. (D) The density of toluene vapor is greater than that of water vapor.

What is [H3O ] in a solution formed by dissolving 1.00 g NH4Cl (M = 53.5) in 30.0 mL of 3.00 M NH3(Kb = 1.8 10-5)? (A) 2.710-9 M (B) 5.510-10 M (C) 1.210-10 M (D) 1.410-12 M

What is the concentration of chloride ions in a solution formed by mixing 150. mL of a 1.50 M NaCl solution with 250. mL of a 0.750 M MgCl2 solution? (A) 0.563 M (B) 1.03 M (C) 1.50 M (D) 2.25 M

What is the geometry of SF4? (A) Tetrahedral (B) Square planar (C) See-saw (D) Trigonal monopyramidal

What volume of 18.0 M sulfuric acid must be diluted to 250.0 mL to afford a 0.55 M solution of sulfuric acid? (A) 3.1mL (B) 4.5mL (C) 7.6mL (D) 31mL

Which class of organic compounds does NOT contain oxygen? (A) Alcohol (B) Amide (C) Amine (D) Ketone

Which compound reacts the fastest in electrophilic aromatic substitution reactions (such as with Br2 in the presence of FeBr3)?

Which element does NOT have multiple allotropes? (A) Carbon (B) Oxygen(C) Fluorine (D) Phosphorus

Which gas at 600 K has the same effusion rate as methane (CH4) at 150 K? (A) He (B) O2 (C) SO2 (D) N2O4

Which is the best way to dispense liquids using a volumetric pipet? (A) The pipet is immersed in the liquid to be dispensed, then lifted with a gloved finger on the top and the liquid allowed to drain to the mark. The remaining contents are then allowed to drain into the desired container. (B) The pipet is immersed in the liquid to be dispensed, then lifted with a gloved finger on the top and the liquid allowed to drain to the mark. The remaining contents are then allowed to drain into the desired container, with a pipet bulb used to gently blow out any residual droplets. (C) The tip of the pipet is submerged below the surface of the liquid and suction is applied using a pipet bulb until the liquid rises above the level of the mark. A gloved finger is then applied to the top of the pipet and the liquid allowed to drain to the mark. The remaining contents are then allowed to drain into the desired container. (D) The tip of the pipet is submerged below the surface of the liquid and suction is applied by mouth until the liquid rises to the level of the mark. The contents are then allowed to drain into the desired container.

Which reactions are spontaneous under standard conditions? I. 2 Cu+(aq) + Co(s) → Co2+(aq) + 2 Cu(s) II. 3 Co2+(aq) + 2 In(s) → 2 In3+(aq) + 3 Co(s) (A) I ONLY (B) II ONLY (C) BOTH I AND II (D) NEITHER I OR II

Which sample contains the smallest number of atoms? (A) 1.0LofAratSTP (B) 1.0LofH2 atSTP (C) 1.0LofArat25oCand760mmHg (D) 1.0LofH2 at0oCand900mmHg

Which sample has the greatest entropy at a given temperature? (A) 2 mol HBr(s) (B) 2 mol HBr(l) (C) 2 mol HBr(g) (D) 1 mol H2(g) + 1 mol Br2(l)

Which species are linear? I. NO2+ II. I3- (A) I only (B) II only (C) Both I and II (D) Neither I nor II

Which species has a normal boiling point closest to the normal boiling point of argon, Ar? (A) H2 (B) N2 (C) F2 (D) Cl2

Which statement about chemical reaction mechanisms is correct? (A) The overall rate law can be determined from any step in the mechanism. (B) The rate of a reaction is the rate of the fastest elementary step of its mechanism. (C) The chemical equation for the sum of all the elementary steps is the chemical equation of the overall reaction. (D) Species that are produced and subsequently consumed in the mechanism serve as catalysts for the reaction.

Which statements correctly describe the geometry of the carbonate ion, CO32-? I. All three carbon-oxygen bond distances are the same. II. All three bond angles are 120o. (A) I only (C) Both I and II (B) II only (D) Neither I nor II

A 0.1 M solution of which salt is the most basic? (A) NaNO3 (B) NaClO4 (C) NaHSO4 (D) NaHCO3

A 1.00 g sample of a silver-containing ore is dissolved in dilute nitric acid. The solution is neutralized and then selectively electrolyzed to deposit the silver metal, requiring 670 s of 0.10 A current. What is the mass percentage of silver in the ore? (A) 2.5% (B) 3.0% (C) 3.7% (D) 7.5%

A 5.0 g sample of calcium nitrate (Ca(NO3)2, M = 164) contaminated with silica (SiO2, M = 60.1) is found to contain 1.0 g calcium. What is the mass percent purity of calcium nitrate in the sample? (A) 20% (B) 24% (C) 73% (D) 82%

A divalent metal ion dissolved in dilute hydrochloric acid forms a precipitate when H2S is bubbled through the solution. Which ion is it? (A) Ca2+ (B) Mn2+ (C) Zn2+ (D) Cd2+

A pure substance is found to rotate the plane of plane- polarized light. Which compound is it?

A sample of 0.900 mol N2O is placed in a sealed container, where it decomposes irreversibly to N2 and O2 in a first-order reaction. After 42.0 min, 0.640 mol N2O remains. How long will it take for the reaction to be 90.0% complete? (A) 13.0 min (C) 131 min (B) 85.4 min (D) 284 min

A sample of water in a movable piston is maintained at 100.0 oC with an external pressure p. Which statement best describes the transformation of some of the liquid water into water vapor? (A) It is spontaneous if p ≥ 1 atm. (B) It is reversible if p = 1 atm and spontaneous if p>1atm. (C) It is nonspontaneous if p ≥ 1 atm. (D) It is reversible if p = 1 atm and nonspontaneous if p > 1 atm.

A six-carbon organic compound containing oxygen is suspected of being either a secondary alcohol or a ketone. Which chemical or physical test would best distinguish between these two possibilities? (A) Water solubility (B) Melting point (C) Treatment with sodium bicarbonate (D) Treatment with acidic dichromate

A solution of 20.0 g of which hydrated salt dissolved in 200 g H2O will have the lowest freezing point? (A) CuSO4•5H2O(M=250) (B) NiSO4•6H2O(M=263) (C) MgSO4•7H2O(M=246) (D) Na2SO4 • 10 H2O (M = 286)

A solution of ammonia, NH3, has pH = 11.50. What is the ammonia concentration? (The pKa of NH4+ is 9.24.) (A) 1.7×10-5 M (C) 5.5 × 10-3 M (B) 3.2×10-3 M (D) 0.58 M

Addition of 6 M HCl to which substance will NOT result in gas evolution? (A) Al (B) Zn (C) K2CO3 (D) NaNO3

Ammonia (NH3) has a higher normal boiling point(-33 oC) than its heavier congeners PH3 (bp -88 oC) or AsH3 (bp -63 oC). Which is the best explanation for this difference? (A) NH3 is trigonal pyramidal and polar while PH3 and AsH3 are trigonal planar and nonpolar. (B) NH3 is much more acidic than PH3 or AsH3. (C) NH3(l) experiences stronger London dispersion forces than PH3(l) or AsH3(l). (D) NH3(l) has extensive hydrogen bonding while PH3(l) and AsH3(l) do not.

Barium chloride reacts with sodium sulfate according to the following equation: BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2 NaCl(aq) A student mixes a solution containing 10.0 g BaCl2 (M = 208.2) with a solution containing 10.0 g Na2SO4 (M = 142.1) and obtains 12.0 g BaSO4 (M = 233.2). What is the percent yield of this reaction? (A) 60.0% (B) 73.1% (C) 93.3% (D) The isolated barium sulfate is most likely wet, since the yield would otherwise be greater than 100%.

Barium fluoride has Ksp = 1.8 × 10-7. What is the maximum fluoride ion concentration possible in a solution with [Ba2+] = 5.0 × 10-4 M? (A) 3.6×10-4 M (B) 3.6×10-3 M (C) 9.5×10-3 M (D) 1.9×10-2 M

Carbon tetrachloride is produced from methyl chloride and chlorine according to the following equation: CH3Cl(g) + 3 Cl2(g) CCl4(g) + 3 HCl(g) If the rate of formation of CCl4 is measured to be 0.063 M min-1, what is the rate of disappearance of Cl2? (A) 0.021 M min-1 (B) 0.063 M min-1 (C) 0.13 M min-1 (D) 0.19 M min-1

Chromium(III) hydroxide has Ksp = 1.6 × 10-30. What is the molar solubility of Cr(OH)3 in a solution whose pH is maintained at 6.00? (A) 1.6 × 10-12 mol L-1 (C) 3.6 × 10-8 mol L-1 (B) 1.6 × 10-8 mol L-1 (D) 1.6 × 10-6 mol L-1

Diamond is an example of what kind of solid? (A) Ionic (B) Metallic (C) Molecular (D) Network covalent

Dissolution of which salt in water results in a decrease in the temperature of the solution? (A) KHSO4 (B) NaOH (C) AlCl3 (D) NH4NO3

Each of the following forms a colored aqueous solution EXCEPT (A) Cr(NO3)3 (C) Cu(NO3)2 (B) Co(NO3)2 (D) Zn(NO3)2

Electrolysis of 1.00 g of a copper(II) salt required passage of 0.100 A of current for 123 min for complete deposition of all the copper metal. What is the copper salt? (A) CuCl2, M = 134.5 (C) Cu(NO3)2, M = 187.6 (B) CuBr2, M = 223.4 (D) Cu(ClO4)2, M = 262.5

For a reversible exothermic reaction, what is the effect of increasing temperature on the equilibrium constant (Keq) and on the forward rate constant (kf)? (A) Keq and kf both increase (B) Keq and kf both decrease (C) Keq increases and kf decreases (D) Keq decreases and kf increases

Given the bond dissociation enthalpies (BDE) below, what is the approximate ∆Hof for H2O(g)? (A) -934 kJ mol-1 (B) -510. kJ mol-1 (C) -429 kJ mol-1 (D) -255 kJ mol-1

How many electrons in a ground-state As atom in the gas phase have quantum numbers n = 3 and l = 1? (A) 1 (B) 2 (C) 3 (D) 6

How many hydrogen atoms are in 2.50 g of pharmacolite, CaHAsO4•2H2O (M = 216.0)? (A) 6.97 × 1021 (B) 2.09 × 1022 C) 2.79 × 1022 (D) 3.48 × 1022

How many hydroxide ions are in 2.5 mol Mg(OH)2? (A) 3.0 1023 (B) 6.0 1023 (C) 1.5 1024 (D) 3.0 1024

How many total orbitals are there with principal quantum number n = 4? (A) 1 (B) 4 (C) 9 (D) 16

Hydrogen peroxide, H2O2(aq), decomposes into water and oxygen. Adding a small amount of FeCl3(aq) increases the rate of gas evolution in this reaction. What is the best description of the role of FeCl3? (A) Transition state (B) Reaction intermediate (C) Heterogeneous catalyst (D) Homogeneous catalyst

If elemental bromine is being formed according to the equation below at a rate of 0.056 M s-1, at what rate is bromide ion being consumed? 5 Br-(aq) + BrO3-(aq) + 6 H+(aq) 3 Br2(aq) + 3 H2O(l) (A) 0.019 M s-1 (B) 0.034 M s-1 (C) 0.056 M s-1 (D) 0.093 M s-1

In comparing two reactions, the reaction with the greater activation energy always has (A) the slower rate. (B) the faster rate. (C) the rate that varies less with temperature. (D) the rate that varies more with temperature.

In the Lewis structure of ozone, O3, what is the formal charge on the central oxygen? (A) 2- (B) 1- (C) 0 (D) 1+

In the galvanic cellSn(s)|Sn (aq)||Cu (aq)|Cu(s) the standard potential is 0.48 V. Starting with standard concentrations, what are the concentrations of Sn2+ and Cu2+ when the cell has discharged to a potential of 0.45 V? (A) [Sn2+ ] = 0.47 M, [Cu2+] = 1.53 M (B) [Sn2+ ] = [Cu2+] = 1.00 M (C) [Sn2+ ] = 1.53 M, [Cu2+] = 0.47 M (D) [Sn2+ ] = 1.82 M, [Cu2+] = 0.18 M

In the guanidinium ion, [C(NH2)3]+, what is the best description of the hybridizations of the nitrogen atoms? (A) All three sp3 (B) Two sp3, one sp2 (C) One sp3, two sp2 (D) All three sp2

In which are the ionic compounds listed in order of increasing magnitude of their lattice energy? (A) CaO<RbI<LiF<LiI (B) RbI<CaO<LiI<LiF (C) LiI<LiF<CaO<RbI (D) RbI<LiI<LiF<CaO

Silver sulfate, Ag2SO4 (M = 311.87), has Ksp = 6.0 10-5. What mass of Ag2SO4 will dissolve per liter of water? (A) 0.019 g (B) 1.7 g (C) 2.4 g (D) 7.7 g

The rate constant for an elementary chemical reaction can be affected by which of the following? I. Reactant concentrations II. Product concentrations (A) I only (B) II only (C) Both I and II (D) Neither I nor II

The reaction of tert-butyl bromide with azide ion in aqueous solution is proposed to proceed by the following mechanism: Assuming that (CH3)3C+(aq) achieves a steady-state concentration, but making no further assumptions about the relative magnitudes of the three rate constants, what is the rate law for this reaction? (A)Rate = k1[(CH3)3CBr] (B)Rate = k2[(CH3)3CBr][N3-] (C) Rate= k1k2[(CH3)3CBr][N3-] k-1[Br -] (D)Rate= k1k2[(CH3)3CBr][N3-] k-1[Br-] + k2[N3-]

The tetramminecopper(II) ion, Cu(NH3)4 , has a formation constant Kf = 1.1 1013. What is the minimum concentration of free ammonia in solution required to ensure that at least 99.9% of the dissolved copper(II) ion is found in the form of its ammonia complex? (A) 910-14 M (B) 910-11 M (C) 810-4 M (D) 310-3 M

What is the maximum number of monosubstitution products of the aromatic substitution reaction shown? (A) 1 (B) 2 (C) 3 (D) 4

What is the pH of a 0.10 M solution of NaCN? The Ka of HCN is 4.9 × 10-10. (A) 2.85 (B) 5.15 (C) 8.85 (D) 11.15

When the chemical equation is balanced, what is the ratio of the coefficient of Ag(s) to the coefficient of H2O(l)? __ Ag(s) + __ NO3-(aq) + __ H+(aq) → __ Ag+(aq) + __ NO(g) + __ H2O(l) (A) 1:1 (B) 2:1 (C) 3:1 (D) 3:2

When the following reaction is balanced, what is the ratio of coefficients of H+(aq) to NO(g)? Cu(s) + H+(aq) + NO3-(aq) NO(g) + H2O(l) + Cu2+(aq) (A) 1 : 1 (B) 2 : 1 (C) 3 : 1 (D) 4 : 1

Which 50-mL container would be most suitable for measuring and dispensing 37 mL of an aqueous solution?

Which alcohol will undergo acid-catalyzed dehydration under the mildest conditions? (A) CH3CH2CH2CH2OH (B) CH3CH2CH(OH)CH3 (C) (CH3)2CHCH2OH (D) (CH3)3COH

Which cation forms a colorless aqueous solution? (A) Co2+ (B) Ni2+ (C) Cu2+ (D) Zn2+

Which compound contains both ionic and covalent bonds? (A) PF3 (B) KF (C) CH3COOH (D) MgSO4

Which element has chemical properties most similar to those of P? (A) N (B) Al (C) S (D) As

Which gas has an effusion rate closest to half that of oxygen gas at a given temperature? (A) H2 (B) He (C) SO2 (D) Xe

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