CHEM 208 Final

Of the elements indicated on the periodic table shown below, which forms the weakest binary acid, H2X or HX, where X = A, B, C or D?

A

A solution with a hydrogen ion concentration of 3.25 × 10-2 M is ________ and has a hydroxide concentration of ________. basic, 3.08 × 10-12 M acidic, 3.08 × 10-13 M basic, 3.08 × 10-13 M acidic, 3.08 × 10-12 M

acidic, 3.08 × 10-13 M

Which type of radiation is least useful for medical applications? gamma radiation (most useful) positron emission beta emission alpha emission

alpha emission

During an electrochemical reaction, electrons move through the external circuit toward the ________ and positive ions in the cell move toward the ________. Answers: cathode, anode cathode, cathode anode, cathode anode, anode

cathode, cathode

The complex cis-[CoCl(NH3)(NH2CH2CH2NH2)2]2+ was resolved into optical isomers in 1911 by Alfred Werner, demonstrating the octahedral geometry of the ion. Name this complex ion cis-amminechlorobis(ethylenediamine)cobalt(II) ion cis-amminechlorobis(ethylenediamine)cobalt(III) ion cis-amminechloroethylenediaminecobalt(III) ion cis-chloroammineethylenediaminecobalt(II) ion

cis-amminechlorobis(ethylenediamine)cobalt(III) ion

What is the oxidation state of the Cr atom in [Ni(en)3]3[Cr(CN)6]2 +2 +4 +3 +5

+3

What oxidation state(s) is(are) exhibited by all first row transition elements except scandium? +3 +2, +3 and +4 +2 +2 and +3

+2

A galvanic cell consists of a La3+/La half-cell and a standard hydrogen electrode. If the La3+/La half-cell standard cell functions as the anode, and the standard cell potential is 2.52 V, what is the standard reduction potential for the La3+/La half-cell? Answers: -0.84 V +2.52 V -2.52 V +0.84 V

-2.52 V

For the reaction shown, ΔG° = 6 kJ. N2O4(g) --> 2NO2(g) Given the above information, what would be the ΔG° value for a reaction in which one mole of NO2 reacts to form 0.5 moles of N2O4(g)?

-3 kJ

The burning of propane can be represented by the following equation: C3H8(g) + 7 O2(g) → 3CO2(g) + 4 H2O(g) Which of the following relationships is true? Δ[C3H8]/Δt = Δ[CO2]/Δt -7Δ[O2]/Δt = +4Δ[H2O]/Δt -3Δ[O2]/Δt = +7Δ[CO2]/Δt +7Δ[O2]/Δt = -4Δ[H2O]/Δt

-3Δ[O2]/Δt = +7Δ[CO2]/Δt

In which of the following solutions would solid PbCl2 be expected to be the least soluble at 25°C? Answers: 0.1 M HCl 0.1 M CaCl2 0.1 M KNO3 0.1 M NaCl

0.1 M CaCl2

Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 28.30 mL of 0.500 M HCl to reach the equivalence point? Answers: 0.708 M 0.208 M 0.353 M 1.21 M

0.708 M

How many lone pairs of electrons are on the Xe atom in XeF6?

1

Given that O2 is paramagnetic and has a bond order of 2, and its highest occupied molecular orbital is antibonding, what would be the expected bond orders for O22- and O22+? 1 for O22- and 3 for O22+ 3/2 for O22- and 5/2 for O22+ 5/2 for O22- and 3/2 for O22+ 3 for O22- and 1 for O22+

1 for O22- and 3 for O22+

Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute. If the half-life for carbon-14 is 5730 years, how old is a wood sample that gives a rate for carbon-14 decay of 3.9 counts per minute? Answers: 6.6 × 103 yr 2.9 × 104 yr 4.6 × 103 yr 1.0 × 104 yr

1.0 × 104 yr Response Feedback: First calculate k from t1/2: k = -ln(1/2)/t1/2 = 0.693/5730 years = 1.21E-4/yr Rearrange the integrated rate law to solve for t: t = k-1(-ln(Nt/No)) = k-1(-ln(Dt/Do)) = (-ln(3.9/13.6))/(1.21E-4/yr) = 1.0E4 years

What is the pH of a 0.020 M HClO4 solution?

1.70

The reaction that occurs in a Breathalyzer, a device used to determine the alcohol level in a person's bloodstream, is given below. If the rate of appearance of Cr2(SO4)3 is 1.24 mol/min at a particular moment, what is the rate of disappearance of C2H6O at that moment? 2 K2Cr2O7+ 8 H2SO4+ 3 C2H6O → 2 Cr2(SO4)3+ 2 K2SO4+ 11 H2O 0.413 mol/min 0.826 mol/min 1.86 mol/min 3.72 mol/min

1.86 mol/min

What is the bond order of He2+?

1/2 (e- in bonding - e- in antibonding/ 2)

Relative to the amount of energy released in a typical chemical reaction, the amount of energy released in a typical fission reaction is about 10^8 times greater. the same. 10^10 times greater. 10 times greater.

10^8 times greater.

What is the pH of a solution made by mixing 30.00 mL of 0.10 M HCl with 40.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive. Answers: 1.85 13.15 12.15 0.85

12.15

What is the activation energy for the destruction of ozone based on the diagram below? 14 kJ 392 kJ 406 kJ none of these

14 kj

The following pictures represent solutions of CaCO3, which may also contain ions other than Ca2+ and CO32- which are not shown. Gray spheres represent Ca2+ ions and unshaded spheres represent CO32- ions. If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored? (1) (2) (3) (4)

2

For a particular battery based on one of the following reactions, E is expected to remain constant with time until the cell reactants are almost completely consumed. Which is the appropriate reaction? 2 NiO(OH)(s) + Cd(s) + 2 H2O(l) → 2 Ni(OH)2(s) + Cd(OH)2(s) Pb(s) + PbO2(s) + 2 H+(aq) + 2 HSO4-(aq) → 2 PbSO4(s) + 2 H2O(l) Zn(s) + 2 MnO2(s) + 2 NH4+(aq) → 2 NH3(aq) + Mn2O3(s) + Zn2+(aq) + H2O(l) Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)

2 NiO(OH)(s) + Cd(s) + 2 H2O(l) → 2 Ni(OH)2(s) + Cd(OH)2(s

The following cell has a potential of 0.45 V at 25°C. Pt(s) ∣ H2(1 atm)|H+(? M) ∣∣ Cl-(1 M) ∣ Hg2Cl2(s)|Hg(l) The standard half-cell potential for the half-reaction Hg2Cl2(s) + 2 e- → 2 Hg(l) + 2 Cl-(aq) is 0.28 V. What is the pH in the anode compartment? HINT: E H2 " H+ = 0.0592 V (pH) Answers: 4.7 12.3 7.6 2.9

2.9

What volume of 5.00 × 10-3 M HNO3 is needed to titrate 100.00 mL of 5.00 × 10-3 M Ca(OH)2 to the equivalence point? 200. mL 50.0 mL 100. mL 12.5 mL

200 mL

The reaction for the decomposition of dinitrogen monoxide gas to form oxygen radicals is: N2O(g) → N2(g) + O(g). If the rate constant is 3.04 × 10-2 s-1 and the frequency factor is 8.00 × 1011 s-1, what is the activation energy for the first-order reaction at 700°C? 0.262 kJ/mol 38.2 kJ/mol 180 kJ/mol 250 kJ/mol

250 kJ/mol

The following pictures represent solutions of CuS, which may also contain ions other than Cu2+ and S2‒ which are not shown. Gray spheres represent Cu2+ ions and dotted spheres represent S2‒ ions. If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are unsaturated? only (2) (3) and (4) only (4) only (3)

3 and 4

When 86222Rn decays in a 5-step series the product is 82210Pb. How many alpha and beta particles are emitted in the decay series? 4 α, 1 β- 1 α, 4 β- 3 α, 2 β- 2 α, 3 β-

3 α, 2 β-

Hydrogen peroxide decomposes to water and oxygen according to the reaction below: 2 H2O2(aq) → 2 H2O(l) + O2(g) In the presence of large excesses of I-ion, the following set of data is obtained. What is the average rate of disappearance of H2O2(aq) in M/s in the first 45.0 seconds of the reaction if 1.00 L of H2O2 reacts at 25°C and 1.00 atm pressure? Time (s) O2 Collected (mL) 0.0 0.00 45.0 2.00 90.0 4.00 135.0 6.00 9.09 × 10-7M/s 3.63 × 10-6M/s 4.33 × 10-5M/s 1.64 × 10-4M/s

3.63 × 10-6M/s

The total binding energies for 3He, 4He, and 6He are 7.72 MeV, 28.29 MeV, and 29.26 MeV respectively. Arrange the 3 isotopes in increasing order of binding energy per nucleon. 4He < 3He < 6He 6He < 4He < 3He 3He < 6He < 4He 3He < 4He < 6He

3He < 6He < 4He

How many unpaired electrons are present in the high spin form of the [CoF6]3- complex and what metal orbitals are used in bonding? Answers: 4 unpaired electrons and 4s, 4p and 4d orbitals to give sp3d2 4 unpaired electrons and 3d, 4s and 4p orbitals to give d2sp3 0 unpaired electrons and 4s, 4p and 4d orbitals to give sp3d2 0 unpaired electrons and 3d, 4s and 4p orbitals to give d2sp3

4 unpaired electrons and 4s, 4p and 4d orbitals to give sp3d2

For a particular first-order reaction, it takes 48 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s-1) for the reaction? 1.0 × 10-4 s-1 4.8 × 10-4 s-1 6.0 × 10-3 s-1 2.9 × 10-2 s-1

4.8 × 10-4 s-1

When the oxalate ion, C2O42- is bonded to the iron(III) ion in the complex ion [Fe(C2O4)3]3-, a ________-membered chelate ring is formed. 4 3 5 6

5

The practical limit for 14C dating occurs when its activity falls to 0.20% of its original value due to interference in detectors by natural background radiation. If the half-life is 5730 years, what is the maximum age of a sample that can be detected by 14C without interference. 2.9 x 106 years 2.9 x 104 years 1.3 x 104 years 5.1 x 104 years

5.1 x 104 years Response Feedback: First calculate k from t1/2: k = -ln(1/2)/t1/2 = 0.693/5730 years = 1.21E-4/yr Rearrange the integrated rate law to solve for t: t = k-1(-ln(Nt/No)) = (-ln(0.002))/(1.21E-4/yr) = 5.1E4 years

A concentration-time study of the gas phase reaction 2 A3→ 3 A2 produced the data in the table below. What is the concentration of A2 after 30 seconds? Time (s) [A3] (M) [A2] (M) 0 4.00 × 10-4 0 10 2.00 × 10-4 3.00 × 10-4 20 1.00 × 10-4 4.50 × 10-4 30 5.00 × 10-5 ?

5.25 × 10-4M

What is the molar solubility of Mg(OH)2 in a basic solution with a pH of 12.00? Ksp for Mg(OH)2 is 5.6 × 10-12 M 1.1 × 10-4 M 5.6 × 10-10 M 5.6 × 10-8 M 2.4 × 10-6 M

5.6 × 10-8 M

The aquation of tris(1, 10-phenanthroline)iron(II) in acid solution takes place according to the equation: Fe(phen)32+ + 3 H3O+ + 3 H2O → Fe(H2O)62+ + 3 phenH+ If the activation energy is 126 kJ/mol and frequency factor is 8.62 × 10^17 s-1, at what temperature is the rate constant equal to 3.63 × 10^-3 s-1 for the first-order reaction? 0°C 36°C 50°C 94°C

50 C

In the relationship △G = - nFE°, what is the value of n for the reaction shown below? 3 Cu2+(aq) + 2 Al(s) → 3 Cu(s) + 2 Al3+(aq) 3 6 1 2

6

What is the coordination number of the Fe atom in K3[Fe(C2O4)3]? 4 3 2 6

6

Which of the following isotopes is the least stable? 23Na, 8.11 MeV/nucleon 94Zr, 8.67 MeV/nucleon 240Pu, 7.26 MeV/nucleon 7Be, 5.37 MeV/nucleon

7Be, 5.37 MeV/nucleon

If four orbitals on one atom overlap four orbitals on a second atom, how many molecular orbitals will form? 2 4 8 16

8

What is the smallest bond angle in SF6? 60° 120° 109.5° 90°

90

The nuclear transmutation reaction that leads to the synthesis of plutonium-241 is shown below. What is the identity of the α-particle bombardment target in this reaction? 96^246Cm 96^245Cm 92^238U 92^237U

92^238U

Which of the following Hg nuclides is most likely to undergo beta decay? A = 195; Z = 80 A = 190; Z = 80 A = 200; Z = 80 A = 205; Z - 80

A = 205; Z - 80

Consider the following table of standard half-cell potentials: A2 + 2 e- → 2 A- E° = + 1.09 V B4+ + 2 e- → B2+ E° = + 0.15 V C3+ + 3 e- → C E° = - 1.66 V D2+ + 2 e- → D E° = - 2.37 V Which substance is the strongest oxidizing agent?

A2

Which element is most likely to have an anomalous electron configuration? Y Ag Cd Tc

Ag

Which of the following metal hydroxides are amphoteric? Cu(OH)2 , Mn(OH)2, Fe(OH)2, Fe(OH)3 LiOH, NaOH, KOH, RbOH Be(OH)2, Ca(OH)2, Ba(OH)2, Sr(OH)3 Al(OH)3, Zn(OH)2, Cr(OH)3, Sn(OH)2

Al(OH)3, Zn(OH)2, Cr(OH)3, Sn(OH)2

Which of the following is not true? The sp3 hybrid orbitals are degenerate. An sp3 hybrid orbital may form a sigma bond by overlap with an orbital on another atom. An sp3 hybrid orbital may hold a lone pair of electrons. An sp3 hybrid orbital may form a pi bond by overlap with an orbital on another atom.

An sp3 hybrid orbital may form a pi bond by overlap with an orbital on another atom.

What is the most soluble salt of the following set? Cd(OH)2 with Ksp = 5.3 × 10-15 Fe(OH)2 with Ksp = 2.5 × 10-37 Ca(OH)2 with Ksp = 4.7 × 10-6 Ba(OH)2 with Ksp = 5.0 × 10-3

Ba(OH)2 with Ksp = 5.0 × 10-3

Compare the energies of molecular orbitals of homonuclear diatomic molecules with the energies of the atomic orbitals with which they correlate. Bonding orbitals are higher and antibonding orbitals are lower in energy than the atomic orbitals. Both bonding and antibonding molecular orbitals are higher in energy than the atomic orbitals. Bonding orbitals are lower and antibonding orbitals are higher in energy than the atomic orbitals. Both bonding and antibonding molecular orbitals lie lower in energy than the atomic orbitals.

Bonding orbitals are lower and antibonding orbitals are higher in energy than the atomic orbitals.

Which drawing represents a σ bonding molecular orbital for a homonuclear diatomic molecule? A B C D

C

Which of the following titrations result in an acidic solution at the equivalence point? Answers: KF titrated with KOH CH3COOH titrated with NaOH C5H5N titrated with HCl HCl titrated with NaOH

C5H5N titrated with HCl

What is the common ion in a solution prepared by mixing 0.10 M NaCH3CO2 with 0.10 M CH3CO2H?

CH3CO2-

A particular 12V battery is based on a reaction having a standard cell potential, E° = +1.92 V. What happens when the battery "dies" ? Answers: E° = +1.92 V and E = 0 V E° = 0 V and E = 12 V E° = +1.92 V and E = 12 V E° = 0 V and E = 0 V

E° = +1.92 V and E = 0 V

The iron content of foods can be determined by dissolving them in acid (forming Fe3+), reducing the iron(III) to iron(II), and titrating with cerium(IV): Fe2+(aq) + Ce4+(aq) → Fe3+(aq) + Ce3+(aq) Identify the two half-reactions in the above reaction. Left = oxidation half reaction; Right = reduction half reactoin Answers: Fe2+(aq) + e-→ Fe3+(aq) Ce4+(aq) → Ce3+(aq) + e- Fe2+(aq) → Fe3+(aq) + e- Ce4+(aq) + e- → Ce3+(aq) Ce4+(aq) + e- → Ce3+(aq) Fe2+(aq) → Fe3+(aq) + e- Ce4+(aq) → Ce3+(aq) + e- Fe2+(aq) + e- → Fe3+(aq)

Fe2+(aq) → Fe3+(aq) + e- Ce4+(aq) + e- → Ce3+(aq)

The equilibrium constant, K, for the reaction shown below has a value 1.8 × 10-5. In this reaction which is the strongest acid and which is the strongest base? CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq)

H3O+ and CH3CO2-

The equilibrium constant, K, for the reaction shown below has a value 1.8 × 10-5. In this reaction which is the strongest acid and which is the strongest base? CH3CO2H(aq) + H2O(l) ⇌ H3O+(aq) + CH3CO2-(aq)

H3O+ and CH3CO2-

Which Brønsted-Lowry acid has the strongest conjugate base? HCl HF HClO4 HNO3

HF

Which is a net ionic equation for the neutralization of a weak acid with a strong base? HCl(aq) + NaOH(aq) ⇌ H2O(l) + NaCl(aq) H3O+(aq) + OH-(aq) ⇌ 2 H2O(l) HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq) HF(aq) + NaOH(aq) ⇌ H2O(l) + NaF(aq)

HF(aq) + OH-(aq) ⇌ H2O(l) + F-(aq)

What is the strongest acid among the following? HBr HI HCl HF

HI

When equal molar amounts of the following sets of compounds are mixed in water, which will not form a buffer solution? Answers: HNO3 with NaNO3 NaH2PO4 with Na2HPO4 NH3 with NH4Cl CH3CO2H with NaCH3CO2

HNO3 with NaNO3

A mechanism for a naturally occurring reaction that destroys ozone is: Step 1: O3(g) + HO(g) → HO2(g) + O2(g) Step 2: HO2(g) + O(g) → HO(g) + O2(g) Which species is a catalyst? HO HO2 O O3

HO

A mechanism for a naturally occurring reaction that destroys ozone is: Step 1: O3(g) + HO(g) → HO2(g) + O2(g) Step 2: HO2(g) + O(g) → HO(g) + O2(g) Which species is an intermediate? Answers: HO HO2 O O3

HO2

Which one of the followig can behave either as a Bronsted Lowry acid or a Bronsted Lowry Base? HI HSO3- H3PO4 NH3

HSO3-

Shown below are the reactions occurring in the direct methanol fuel cell (DMFC). I 2 CH3OH(aq) + 2 H2O(l) → 2 CO2(g) +12 H+(aq) +12 e- II 3 O2(g) + 12 H+(aq) + 12 e- → 6 H2O(l) Overall 2 CH3OH(aq) + 3 O2(g) → 2 CO2(g) + 4 H2O(l) Which is the anode reaction, and what is being oxidized in the overall reaction? I, H2O II, O2 I, CH3OH II, H+

I, CH3OH

Which of the following would be expected to have sp2 hybridization on atom A?

I, II, III

Which of the following statements are true about reaction mechanisms? I. A rate law can be written from the molecularity of the slowest elementary step. II. The final rate law can include intermediates. III. The rate of the reaction is dependent on the fastest step in the mechanism. IV. A mechanism can never be proven to be the correct pathway for a reaction. I, II, III II, IV I, III I, IV

I, IV

When dissolved in water, which of the following compounds is an Arrhenius base? KOH HOCl KCL CH3OH

KOH

What is the equilibrium constant expression (Ka) for the acid dissociation of hydrocyanic acid HCN? The equation of interest is HCN(aq) + H2O(l) ⇌ H3O+(aq) + CN-(aq).

Ka = ([H3O+][CN-])/([HCN])

What is the equilibrium constant expression (Kb) for the base dissociation of ammonia NH3? The equation of interest is NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq). Kb = ([NH4+][OH-])/([NH3][H2O]) Kb = ([NH3])/([NH4+][OH-]) Kb = ([NH3][H2O])/([NH4+][OH-] Kb = ([NH4+][OH-])/([NH3])

Kb = ([NH4+][OH-])/([NH3])

The balanced equation for the solubility equilibrium of Fe(OH)2 is shown below. What is the equilibrium constant expression for the Ksp of Fe(OH)2? Answers: Ksp = {[Fe2+][OH-]2}/[Fe(OH)2] Ksp = [Fe2+][OH-]2 Ksp = {[Fe2+][OH-]2}/{[Fe(OH)2][H2O]} Ksp = 1/{[Fe2+][OH-]2}

Ksp = [Fe2+][OH-]2

If the units for rate are M s-1, what are the units for the rate constant, k, if the overall order of the reaction is three? Answers: s-1 M2s-1 M-1s-1 M-2 s-1

M-2 s-1

What are the conjugate acid-base pairs in the following chemical reaction? NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq) NH3, H2O and NH4+, OH- NH3, OH- and H2O, NH4+ NH3 and NH4+ NH3, NH4+ and H2O, OH-

NH3, NH4 and H20, OH-

Which metal ion is most likely to form a square planar complex ion with CN-? Co2+ Zn2+ Ni2+ Cu2+

Ni 2+

Which one of the following statements about isotopes is false? Nonradioactive isotopes generally have an odd number of neutrons. The ratio of neutrons to protons is > 1:1 for elements heavier than Ca. The ratio of neutrons to protons is about 1:1 for elements lighter than Ca. All isotopes beyond 209Bi are radioactive.

Nonradioactive isotopes generally have an odd number of neutrons.

SO3 reacts with H2O to form H2SO4. Which picture below correctly represents the curved arrow notation for the initial Lewis acid-Lewis base interaction in this reaction; what is the Lewis acid and the Lewis base? Picture (1) is correct; H2O is the Lewis acid and SO3 is the Lewis base. Picture (2) is correct; H2O is the Lewis acid and SO3 is the Lewis base. Picture (1) is correct; SO3 is the Lewis acid and H2O is the Lewis base. Picture (2) is correct; SO3 is the Lewis acid and H2O is the Lewis base.

Picture (2) is correct; SO3 is the Lewis acid and H2O is the Lewis base.

What is the shorthand notation that represents the following galvanic cell reaction? 2 Fe2+(aq) + Cl2(g) → 2 Fe3+(aq) + 2 Cl-(aq) Answers: Fe(s) ∣ Fe2+(aq) ∣∣ Fe3+(aq), Cl2(g) ∣ Cl-(aq) ∣ C(s) Fe2+(aq) ∣ Fe3+(aq) ∣∣ Cl2(g) ∣ Cl-(aq) Pt(s) ∣ Fe2+(aq), Fe3+(aq) ∣∣ Cl2(g) ∣ Cl-(aq) ∣ C(s) Pt(s) ∣ Fe3+(aq), Fe2+(aq), Cl2(g) ∣∣ Cl-(aq) ∣ C(s)

Pt(s) ∣ Fe2+(aq), Fe3+(aq) ∣∣ Cl2(g) ∣ Cl-(aq) ∣ C(s)

What is the rate law for the elementary reaction shown below? 2 HI → H2 + I2 Rate = k[HI] Rate = k[HI]2 Rate = k[H2][I2] Rate = k[H2][I2]/[HI]2

Rate = k[HI]2

The following set of data was obtained by the method of initial rates for the reaction: 2 HgCl2(aq) + C2O4-2 (aq) → 2 Cl-(aq) + 2 CO2(g) + Hg2Cl2(s) What is the rate law for the reaction? [HgCl2] (M) [C2O4-2] (M) Rate (M/s) 0.10 0.10 1.3 x 10-7 0.10 0.20 5.2 x 10-7 0.20 0.20 1.0 x 10-6 Rate = k[HgCl2][C2O42-]-2 Rate = k[HgCl2][C2O42-]-1 Rate = k[HgCl2]2[C2O42-] Rate = k[HgCl2][C2O42-]2

Rate = k[HgCl2][C2O42-]2

When the concentration of A is doubled, the rate for the reaction: 2 A + B → 2 C quadruples. When the concentration of B is doubled the rate remains the same. Which mechanism below is consistent with the experimental observations? Answers: Step 1: A + B ⇌ D (fast equilibrium) Step 2: A + D → 2 C (slow) Step 1: A + B → D (slow) Step 2: A + D ⇌ 2 C (fast equilibrium) Step 1: 2 A → D (slow) Step 2: B + D → E (fast) Step 3: E → 2 C (fast) Step 1: 2 A ⇌ D (fast equilibrium) Step 2: B + D → E (slow) Step 3: E → 2 C (fast)

Step 1: 2 A → D (slow) Step 2: B + D → E (fast) Step 3: E → 2 C (fast)

For transition elements, which of the following occurs as the effective nuclear charge increases? Both the atomic radius and the density increase. The atomic radius decreases and the density increases. The atomic radius increases. Electron density increases.

The atomic radius decreases and the density increases.

Which of the following statements concerning the rusting of iron is false? The oxidation site can occur at a different place on the metal surface than the reduction site. Salt increases the rate of corrosion by providing ions to carry the current. The rusting of iron requires both oxygen and water. The metal is reduced.

The metal is reduced.

Which statement is true about the formation of CO2(g) and 2H2O(g) from CH4(g) and 2O2(g) at 1.00 atm? CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) ΔH° = -803 kJ and ΔS° = -4 J/K The reaction is spontaneous at all temperatures. The reaction is spontaneous at low temperatures. The reaction is spontaneous at high temperatures. The reaction is not spontaneous at any temperature

The reaction is spontaneous at low temperatures.

Which statement is true for the general rate law: Rate = k[A]m[B]n? Answers: It can be written from the stoichiometry of the overall reaction. The overall order of the reaction is equal to m times n. The values for the exponents must be determined by experiment. The exponents in the rate law must be positive integers.

The values for the exponents must be determined by experiment.

A triple bond is generally composed of one π bond and two σ bonds. three π bonds three σ bonds. two π bonds and one σ bond.

Two π bonds and one σ bond.

The masses of 4He, 6Li, and 10B are 4.0015, 6.0135, and 10.0102 amu respectively. The fission of a boron-10 nucleus into He-4 and Li-6 would evolve energy. absorb energy. result in no energy change. Need more information

absorb energy.

Ionizing radiation having the lowest energy is exhibited by X-rays. β particles. α particles. γ rays.(highest)

X-rays.

What is the ground-state electron configuration for the element chromium (Z = 24)? Answers: [Ar] 4s1 3d5 [Ar] 4s2 3d4 [Ne] 4s2 3d4 [Ar] 3d6

[Ar] 4s1 3d5

Which pair of isomers illustrates the concept of ionization isomers? [CoCl(NH3)5]SO4 and [Co(SO4)(NH3)5]Cl cis -[PtCl2(NH3)2] and trans -[PtCl2(NH3)2] [Cr(SCN)(NH3)5]2+ and [Cr(NCS)(NH3)5]2+ (+)-[Co(en)3]3+ and (-)-[Co(en)3]3+

[CoCl(NH3)5]SO4 and [Co(SO4)(NH3)5]Cl

Write the chemical formula for aquabromobis(ethylenediamine)chromium(III) chloride. [Cr(H2O)Br2(en)]Cl2 [Cr(H2O)Br(en)2]Cl3 [Cr(H2O)Br(en)]Cl [Cr(H2O)Br(en)2]Cl2

[Cr(H2O)Br(en)2]Cl2

A chromium(III) ion forms a complex ion with two ammonia molecules and four thiocyanate ions. What is the formula of the complex ion? [Cr(NH4)2(NCS)4]+ [Cr(NH3)2(NCS)4]3+ [Cr(NH3)2(NCS)4]4- [Cr(NH3)2(NCS)4]-

[Cr(NH3)2(NCS)4]-

An acidic solution at 25 °C has Answers: [H3O+] > 1 × 10-7 M > [OH-] [H3O+] < 1 × 10-7 M > [OH-] [H3O+] > [OH-] > 1 × 10-7 M [H3O+] = [OH-] > 1 × 10-7 M

[H3O+] > 1 × 10-7 M > [OH-]

Which ion has cis and trans isomers? [PtCl2(CN)2]2- [Pt(CN)5NH3]- [Pt(C2O4)2]2- [PdCl3NH3]-

[PtCl2(CN)2]2-

An electrolytic cell is Answers: a battery. a cell in which the cell reaction is spontaneous. a cell in which an electric current drives a nonspontaneous reaction. a cell in which reactants are continuously supplied to the cell.

a cell in which an electric current drives a nonspontaneous reaction.

The C=O bond in COCl2 can be described as a σ bond involving an sp2 hybrid orbital on C and a π bond involving a p orbital on C. a σ bond involving an sp hybrid orbital on C and a π bond involving a p orbital on C. a σ bond and a π bond, both involving sp2 hybrid orbitals on C. a σ bond and a π bond, both involving sp hybrid orbitals on C.

a σ bond and a π bond, both involving sp2 hybrid orbitals on C.

If an equal number of moles of the weak acid HCN and the strong base KOH are added to water, is the resulting solution acidic, basic, or neutral?

basic

A radioisotope has a neutron/proton ratio which is too low. Which of the following processes will not occur for such a nucleus? Answers: alpha emission beta emission positron emission electron capture

beta emission

Which process decreases the neutron/proton ratio? Answers: positron emission alpha emission electron capture beta emission

beta emission

The orbital hybridization on the Se atom in SeF6 is sp2 sp3 dsp3 d2sp3

d2sp3

The following pictures represent aqueous solutions of binary acids of the type hA where the water molecules have been omitted for clarity. Arrange the acids in order of increasing acid strength. D < B < A < C D < A < C < B D < C < B < A D < C < A < B

d<a<c<b

When 50 mL of 0.10 M NH4Cl is added to 50 mL of 0.10 M NH3, relative to the pH of the 0.10 M NH3 solution the pH of the resulting solution will

decrease

For an octahedral complex, what metal d orbitals have lobes directed towards the ligands? dz², dxz, dyz dxy, dxz, dyz dxy, dxz dz², dx²-y²

dz², dx²-y²

The fraction of collisions with sufficient energy to react is equal to: Answers: A Ea e-Ea/RT p

e-Ea/RT

Which one of the following instruments would be least suitable for detecting particles given off by radioactive decay? (best-grieger counter)

electron microscope

Four heavy elements (A, B, C, and D) will fission when bombarded by neutrons. In addition to fissioning into two smaller elements, A also gives off a beta particle, B gives off gamma rays, C gives off neutrons, and D gives off alpha particles. Which element would make a possible fuel for a nuclear reactor? element C element B element A element D

element C

Which definition best describes isomers that are non-superimposable mirror images of each other that rotate plane polarized light to the same degree but in opposite directions? linkage isomers racemic mixture diastereoisomers enantiomers

enantiomers

Precipitation of an ionic compound will occur upon mixing of desired reagents if the initial ion product is Answers: less than the Ksp. equal to the Ksp. greater than the Ksp. equal to the pKsp.

greater than the Ksp.

The MO diagram below is appropriate for B2. Based on this diagram, B2 has a bond order of one and is diamagnetic. has a bond order of two and is paramagnetic. has a bond order of two and is diamagnetic. has a bond order of one and is paramagnetic.

has a bond order of one and is paramagnetic.

What is the crystal field energy level diagram for the complex [Fe(H2O)6]3+?

high spin; octahedral

Which is the only element that contains more protons than neutrons in its most abundant stable isotope? Answers: boron hydrogen mercury carbon

hydrogen

For a reaction that follows the general rate law, Rate = k[A][B]2, what will happen to the rate of reaction if the concentration of B is increased by a factor of 2.00? The rate will decrease by a factor of 1/4.00. decrease by a factor of 1/2.00. increase by a factor of 2.00. increase by a factor of 4.00.

increase by a factor of 4.00.

Consider the galvanic cell, Pb(s)|Pb2+(aq)||Cu2+(aq)|Cu(s) Which one of the following changes to the cell would cause the cell potential to increase (i.e., become more positive)? HINT: Ecell = Ecell° - (RT/nF) lnQ Answers: increase the [Pb2+] concentration increase the mass of Pb(s) decrease the mass of Pb(s) increase the [Cu2+] concentration

increase the [Cu2+] concentration

As the atomic number of the elements increases, the ratio of neutrons to protons in stable nuclei: increases. is unrelated to stability. decreases. stays the same.

increases

When the temperature of a gas whose activation energy is 55 kJ/mol is increased from 300 K to 320 K, the fraction of collisions with sufficient energy to react decreases by a factor of 2. decreases by a factor of 4. increases by a factor of 2. increases by a factor of 4.

increases by a factor of 4.

Identify the classification of isomers illustrated by [Co(NO2)(NH3)5]2+ and [Co(ONO)(NH3)5]2+ Answers: optical isomers ionization isomers linkage isomers geometric isomers

linkage isomers

A steel pipe can be protected from corrosion by attaching the pipe to a piece of magnesium because magnesium is more easily oxidized than iron. magnesium and steel form a corrosion resistant alloy. magnesium is inert. magnesium forms a tight oxide coating.

magnesium is more easily oxidized than iron

The paramagnetism of O2 is explained by molecular orbital theory. valence bond theory. resonance. coordinate covalent bonding.

molecular orbital theory

Which of the following best describes ICl2-? It has a molecular geometry that is linear molecular shape with lone pairs on the I atom. non-linear molecular shape with lone pairs on the I atom. non-linear molecular shape with no lone pairs on the I atom. linear molecular shape with no lone pairs on the I atom.

non-linear molecular shape with lone pairs on the I atom.

In the two half-reactions shown below, which chromium species is the strongest oxidizing agent? Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l) E° = + 1.33 V CrO42-(aq) + 4 H2O(l) + 6 e- → Cr(OH)3(s) + 5 OH-(aq) E° = - 0.13 V Answers: Cr(OH)3 Cr2O72- Cr3+ CrO42-

oxidizing agent are themselves reduced Selected Answer: Cr2O72-

What is the pH at the equivalence point of a weak acid-strong base titration? Answers: pH = 14.00 pH < 7 pH > 7 pH = 7

pH > 7

Which term describes the measure of the increase in the concentration of a product per unit time? activation energy kinetics reaction rate reaction time

reaction rate

Molecular orbitals extending over more than two atoms provide an explanation for resonance. coordinate covalent bonding. ionic bonding. paramagnetism.

resonance

The orbital hybridization on the carbon atom in HCN is sp3. none of the above. sp2. sp.

sp

Aluminum requires relatively little protection from corrosion because the oxidation of aluminum produces a hard, relatively impenetrable film of Al2O3. the reduction potential for Al3+/Al is very low. aluminum has little tendency to react with oxygen. aluminum is protected by cathodic protection.

the oxidation of aluminum produces a hard, relatively impenetrable film of Al2O3.

How many resonance structures are required in the electron-dot structure of CO32-? four two three five

three

What is the molecular geometry of AsCl3?

trigonal pyramidal

Elements with ________ atomic mass are best possible candidates for a fission reaction. Answers: moderate very low very heavy moderate to heavy

very heavy

If Q increases... Answers: ΔG increases and the reaction becomes more spontaneous. ΔG decreases and the reaction becomes less spontaneous. ΔG decreases and the reaction becomes more spontaneous. ΔG increases and the reaction becomes less spontaneous.

ΔG increases and the reaction becomes less spontaneous.

The figure above represents the nonspontaneous reaction O2(g) → 2O(g). What are the signs (+ or -) of ΔH, ΔS, and ΔG for this process? Answers: ΔH = +, ΔS = +, ΔG = - ΔH = +, ΔS = +, ΔG = + ΔH = -, ΔS = -, ΔG = - ΔH = -, ΔS = -, ΔG = +

ΔH = +, ΔS = +, ΔG = +

Which molecular orbitals for homonuclear diatomic molecules are degenerate? π molecular orbitals σ molecular orbitals π molecular orbitals and σ molecular orbitals neither π molecular orbitals nor σ molecular orbitals

π molecular orbitals