Chem 28884 | Course Paper

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In an octahedral complex, electrons in and orbitals experience a greater

repulsion from the lone pairs of electrons on ligands because these orbitals

A.contain more electrons than the other three d orbitals.

B.each contain one unpaired electron.

C.are oriented directly toward the incoming ligand electron pairs.

D.are located a greater distance from the metal ion nucleus.

E.are roughly spherical in shape, much like an s orbital.

Potassium hydrogen phthalate (KHP) is used to standardize sodium hydroxide. If 35.39

mL of NaOH(aq) is required to titrate 0.8246 g KHP to the equivalence point, what is

the concentration of the NaOH(aq)? (The molar mass of KHP = 204.2 g/mol)

HC8H4O4

“(aq) + OH“(aq) C8H4O4

2″(aq) + H2O( )

A.0.02318 M

B.0.05705 M

C.0.0859 M

D.0.1141 M

E.0.1429 M

Which of the following compounds is a weak base?

A.NaOH

B.H2CO3

C.LiCl

D.NH3

E.CH3CO2H

What is the distance, in atomic radii (r), along any edge of a primitive unit cell?

A.r

B.2 r

D.4 r

What is the oxidation number of each atom in sulfurous acid, H2SO3?

A.H = +1, S = “2, O = “2

B.H = 0, S = +6, O = “2

C.H = 0, S = 0, O = 0

D.H = +1, S = +4, O = “2

E.H = “1, S = +8, O = “2

Which of the following statements is/are CORRECT? If an ionic compound with the

formula MX forms a face-centered cubic unit cell with the anions (Xn“) at the lattice

points, the cations (Mn+) may occupy

1/ one fourth of the tetrahedral holes in each unit cell.

2/ all of the octahedral holes in each unit cell.

3/ the center of each face in each unit cell.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2, and 3

The central atom in SCl2 is surrounded by

A.two single bonds and no lone pairs of electrons.

B.two single bonds and one lone pair of electrons.

C.two single bonds and two lone pairs of electrons.

D.one single bond, one double bond, and no lone pairs of electrons.

E.one single bond, one double bond, and one lone pair of electrons.

In molecules, as bond order increases,

A.both bond length and bond energy increase.

B.both bond length and bond energy decrease.

C.bond length increases and bond energy is unchanged.

D.bond length is unchanged and bond energy increases.

E.bond length decreases and bond energy increases.

Write a balanced chemical equation for the following reaction in an acidic solution.

Cr2O7

2″(aq) + Ni(s) Cr3+(aq) + Ni2+(aq)

A.Cr2O7

2″(aq) + 3 Ni(s) + 14 H+(aq) 2 Cr3+(aq) + 3 Ni2+(aq) + 7 H2O( )

B.Cr2O7

2″(aq) + Ni(s) + 14 H+(aq) 2 Cr3+(aq) + Ni2+(aq) + 7 H2O( )

C.Cr2O7

2″(aq) + 3 Ni(s) 2 Cr3+(aq) + 3 Ni2+(aq) + O2″(aq)

D.Cr2O7

2″(aq) + Ni(s) + 14 H+(aq) 2 Cr3+(aq) + Ni2+(aq) + 7 H2O( )

E.Cr2O7

2″(aq) + 3 Ni(s) + 7 H+(aq) 2 Cr3+(aq) + 3 Ni2+(aq) + 7 OH“(aq)

The reaction of NO and O2 produces NO2.

2 NO(g) + O2(g) 2 NO2(g)

The reaction is second-order with respect to NO(g) and first-order with respect to

O2(g). At a given temperature, the rate constant, k, equals 4.7 102 M“2s“1. What is the

rate of reaction when the initial concentrations of NO and O2 are 0.025 M and 0.015 M,

respectively?

A.2.6 10“3 M/s

B.4.4 10“3 M/s

C.0.18 M/s

D.2.0 10“8 M/s

E.3.8 102 M/s

Which of the following statements is/are correct?

1/ The atom with the greatest electronegativity is usually the central atom in a molecule.

2/ Electronegativity increases down each group of the periodic table.

3/ As the difference in electronegativity between two bonded atoms increases, the

percent ionic character of the bond increases.

A.1 only

B.2 only

C.3 only

D.2 and 3

E.1, 2, and 3

Which combination of atoms is most likely to produce a compound with covalent

bonds?

A.K and Br

B.Al and S

C.S and Cl

D.Sn and F

E.Li and I

What is the conjugate base of [Fe(H2O)6]3+(aq)?

A.H3O+

B.[Fe(H2O)6]2+

C.[Fe(H2O)5H3O]4+

D.[Fe(H2O)5OH]2+

E.[Fe(H2O)5]3+

Arrange HF, HCl, and HBr in order from lowest to highest boiling point.

A.HF < HCl < HBr

B.HF < HBr < HCl

C.HBr < HF < HCl

D.HBr < HCl < HF

E.HCl < HBr < HF

For the second-order reaction below, the initial concentration of reactant A is 0.24 M. If

the rate constant for the reaction is 1.5 10“2 M“1s“1, what is the concentration of A after

265 seconds?

2A B + C rate = k[A]2

A.0.12 M

B.0.19 M

C.0.95 M

D.4.0 M

E.5.2 M

is used in many home smoke alarms. If 85% of the americium in a smoke

detector decays in 1250 years, what is the half-life of this isotope?

A.1.52 10“3 yr

B.7.35 102 yr

C.5.33 103 yr

D.5.78 103 yr

E.4.57 102 yr

Aluminum crystallizes in a face-centered unit cell. If the length of an edge of the unit

cell is 404 pm, what is the radius of an aluminum atom (in pm)?

A.101 pm

B.143 pm

C.175 pm

D.202 pm

E.286 pm

Which of the following is a correct Lewis structure for sulfate ion?

When mixed in appropriate amounts, each of the following mixtures can produce an

effective buffer solution EXCEPT

A.HCl and NaH2PO4

B.Na2HPO4 and Na3PO4.

C.NaHCO3 and Na2CO3.

D.NaH2PO4 and Na2HPO4.

E.NaOH and NaF.

For which one of the following reactions does Kp equal Kc?

A.2 CO2(g) 2 CO(g) + O2(g)

B.CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g)

C.C(s) + H2O(g) H2(g) + CO(g)

D.NH3(g) 3/2 H2(g) + 1/2 N2(g)

E.2 O3(g) 3 O2(g)

The volume of space occupied by a carbon atom is 1.9 106 pm3. What is the volume of

a carbon atom in cubic meters?

A.1.9 10“30 m3

B.1.9 10“21 m3

C.1.9 10“12 m3

D.1.9 106 m3

E.1.9 1024 m3

Atomic orbitals combine most effectively to form molecular orbitals when

A.electrons in the orbitals have no spins.

B.electrons in the orbitals have the same spin.

C.the atoms have an equal number of valence electrons.

D.the atomic orbitals have similar energies.

E.only d-orbitals are used in bonding.

At what temperatures will a reaction be spontaneous if DrH = +117 kJ and DrS = “35

J/K?

A.All temperatures below 94.1 K

B.Temperatures between 12.7 K and 135 K

C.All temperatures above 94.1 K

D.The reaction will be spontaneous at any temperature.

E.The reaction will never be spontaneous.

What is the pH of the solution which results from mixing 50.0 mL of 0.30 M HF(aq)

and 50.0 mL of 0.30 M NaOH(aq) at 25 C? (Ka of HF = 7.2 10“4)

A.1.98

B.5.84

C.8.16

D.10.85

E.12.02

A solution is prepared by diluting 0.055 mol HNO3 with water to a volume of 1.75 L.

What is the pH of the solution?

A.-1.50

B.0.031

C.1.26

D.1.50

E.12.50

An SHE electrode has been assigned a standard reduction potential, E, of 0.00 Volts.

Which reaction occurs at this electrode?

A.2 H2O( ) + 2 e“ H2(g) + 2 OH“(aq)

B.O2(g) + 4 e“ 2 O2″(aq)

C.Hg2Cl2(s) + 2 e“ 2 Hg( ) + 2 Cl“(aq)

D.Li+(aq) + e“ Li(s)

E.2 H+(aq) + 2 e“ H2(g)

Dichloromethane, CH2Cl2, is a common organic solvent. Which of the following

statements concerning dichloromethane is/are CORRECT?

1/ CH2Cl2 has two isomers. For one isomer of CH2Cl2, the chlorine atoms are adjacent

to each other and the molecule is polar.

2/ CH2Cl2 has two isomers. For one isomer of CH2Cl2, the chlorine atoms are on

opposites sides of the carbon atom and the molecule is nonpolar.

3/ The hybridization of the central carbon atom is sp3.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2, and 3

Polyethylene is a polymer consisting of only carbon and hydrogen. If 2.300 g of the

polymer is burned in oxygen it produces 2.955 g H2O and 7.217 g CO2. What is the

empirical formula of polyethylene?

A.CH

B.CH2

C.C2H3

D.C5H8

E.C7H8

At 25 C, all of the following ions produce an acidic solution, except ____.

A.NH4

B.HSO3

“

C.HPO4

2″

D.[Fe(H2O)6]3+

E.[Al(H2O)6]3+

Calculate the standard reduction potential for the following reaction at 25 C,

AuCl4

“(aq) + 3 e“ Au(s) + 4 Cl“(aq)

given the following thermodynamic information.

Au3+(aq) + 3 e“ Au(s) E = +1.50 V

Au3+(aq) + 4 Cl“(aq) AuCl4

“(aq) Kf = 2.3 1025

A.”1.28 V

B.”0.50 V

C.+1.00 V

D.+1.28 V

E.+3.85 V

Nickel has a face-centered cubic cell, and its density is 8.90 g/cm3. What is the radius

(in pm) of a nickel atom? (The molar mass of nickel is 58.69 g/mol)

A.62.3 pm

B.88.1 pm

C.125 pm

D.249 pm

E.535 pm