Chem 14001 | Course Paper

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You can identify a metal by carefully determining its density. A 29.51 g sample of an

unknown metal is 1.50 cm long, 2.50 cm wide, and 1.00 cm thick. What is a possible

identity of the element?

A.nickel, 8.90 g/cm3

B.aluminum, 2.70 g/cm3

C.silver, 10.5 g/cm3

D.iron, 7.87 g/cm3

E.chromium, 7.20 g/cm3

How many isomers, both structural and geometric, exist for C5H12?

A.3

B.4

C.5

D.7

E.9

Given the following chemical equilibria,

N2(g) + O2(g) 2 NO(g) K1

N2(g) + 3 H2(g) 2 NH3(g) K2

H2(g) + 1/2 O2(g) H2O(g) K3

Determine the method used to calculate the equilibrium constant for the reaction below.

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) Kc

Which of the following statements is/are CORRECT?

1/ For a chemical system, if the reaction quotient (Q) is greater than K, reactant must be

converted to products to reach equilibrium.

2/ For a chemical system at equilibrium, the forward and reverse rates of reaction are

equal.

3/ For a chemical system at equilibrium, the concentrations of products divided by the

concentrations of reactants equals one.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2, and 3

Which of the following statements is/are CORRECT according to valence bond theory?

1/ The overlap between an s orbital and a p orbital is called a pi-bond.

2/ The overlap of two s orbitals in H2 is called a sigma bond.

3/ HF is formed from the overlap of a hydrogen 1s orbital with a fluorine 2p orbital.

A.1 only

B.2 only

C.3 only

D.2 and 3

E.1, 2, and 3

When both of the electrons in a molecular bond originate from the same atom, the bond

is called a(n)

A.sigma bond.

B.coordinate covalent bond.

C.pi bond.

D.metallic bond.

E.ionic bond.

At 25 C, a bottle contains 2.00 L of water in its liquid state. What is the volume of the

water after it freezes (at 0 C)? The densities of liquid water and ice are 0.997 g/mL and

0.917 g/mL, respectively.

A.1.09 L

B.1.84 L

C.2.00 L

D.2.17 L

E.2.19 L

When a real gas is compressed from low pressure to a higher pressure, its temperature

increases. Predict the signs of of DH and DS.

A.DH < 0 and DS < 0

B.DH < 0 and DS > 0

C.DH > 0 and DS < 0

D.DH > 0 and DS > 0

E.DH < 0 and DS = 0

What is the molecular geometry around a central atom that is sp2 hybridized, has three

sigma bonds, and one pi bond?

A.trigonal-planar

B.trigonal-pyramidal

C.bent

D.T-shaped

E.tetrahedral

If an octahedral iron(II) complex is diamagnetic, which of the following sets of

conditions best describes the complex?

A.low-spin, D0 small

B.low-spin, D0 large

C.high-spin, D0 small

D.high-spin, D0 large

E.none of these

Which of the following statements concerning real gases is/are CORRECT?

1/ Real gases are always liquids or solids at temperatures below 273.15 K.

2/ The pressure of a real gas is higher than predicted by the ideal gas law.

3/ The molecules in a real gas are attracted to each other.

A.1 only

B.2 only

C.3 only

D.2 and 3

E.1, 2 and 3

What is the mass of potassium iodide in 50.0 mL of 5.75 10“2 M KI(aq)?

A.2.88 10“2 g

B.191 10“1 g

C.6.92 10“3 g

D.4.77 10“1 g

E.191 102 g

Which of the following statements is/are CORRECT?

1/ Thermoplastics are a class of polymers that will not decompose at temperatures as

great as 700 C.

2/ Thermosetting plastics harden when heated, but they regain their elasticity when

cooled.

3/ Elastomers are materials that spring back to their original shape when stretched.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2, and 3

Which element has the following ground state electron configuration?

A.Fe

B.Co

C.Ni

D.Cu

E.Zn

Using the thermodynamic data below, and a value of “717 kJ/mole for the lattice

enthalpy for KCl, calculate the ionization energy of K.

Enthalpy of atomization of K +89 kJ/mol

Enthalpy of formation of solid KCl “437 kJ/mol

Enthalpy of formation of Cl(g) +121 kJ/mol

Electron affinity of Cl(g) “349 kJ/mol

A.”576 kJ/mol

B.+141 kJ/mol

C.+419 kJ/mol

D.+576 kJ/mol

E.+597 kJ/mol

The rate constant at 366 K for a first-order reaction is 7.7 10“3 s“1 and the activation

energy is 15.9 kJ/mol. What is the value of the frequency factor, A, in the Arrhenius

equation? (R = 8.314 J/Kmol)

A.0.0047 s“1

B.0.70 s“1

C.0.93 s“1

D.1.1 s“1

E.1.4 s“1

What is the balanced chemical equation for the complete combustion of benzoic acid,

C6H5CO2H, to form carbon dioxide and water?

A.C6H5CO2H(s) 6 C(s) + CO2(g) + 3 H2(g)

B.C6H5CO2H(s) 7 CO2(g) + 3 H2O(g)

C.C6H5CO2H(s) + O2(g) CO2(g) + H2O(g)

D.C6H5CO2H(s) + 8 O2(g) 7 CO2(g) + 3 H2O(g)

E.2 C6H5CO2H(s) + 15 O2(g) 14 CO2(g) + 6 H2O(g)

Given the following equilibrium constants,

Ka (HSO4

“) = 1.2 10“2

Kb (CH3CO2

“) = 5.6 10“10

Kw = 1.00 10“14

determine the equilibrium constant for the reaction below at 25 C.

HSO4

“(aq) + CH3CO2

“(aq) SO4

2″(aq) + CH3CO2H(aq)

A.6.7 10“12

B.2.1 10“7

C.1.5 10“3

D.6.7 102

E.2.1 107

A 10.0 L flask at 318 K contains a mixture of Ar and CH4 with a total pressure of 1.040

atm. If the mole fraction of Ar is 0.715, what is the mass percent of Ar?

A.13.8%

B.68.8%

C.71.5%

D.82.9%

E.86.2%

What halogen is in the third period?

A.S

B.Cl2

C.I2

D.H2

E.Ar

A student uses a balance to determine the mass of an object as 5.719 grams. The correct

mass of the object is 5.586 grams. What is the percent error in the student’s mass

determination?

A.2.38%

B.0.133%

C.13.3%

D.74.3%

E.97.7%

Commercial cold packs consist of solid ammonium nitrate and water. NH4NO3 absorbs

25.69 kJ of heat per mole dissolved in water. In a coffee-cup calorimeter, 5.60 g

NH4NO3 is dissolved in 100.0 g of water at 22.0 C. What is the final temperature of the

solution? Assume that the solution has a specific heat capacity of 4.18 J/gK.

A.0.0 C

B.17.9 C

C.11.6 C

D.”54.8 C

E.26.1 C

All of the following relationships are true EXCEPT

A. .

B. .

C. .

D. .

E. .

Which of the following statements concerning isomers is/are correct?

1/ Two types of stereoisomers exist: geometric isomers and optical isomers.

2/ Optical isomers are molecules with nonsuperimposable mirror images.

3/ Ethanol (CH3CH2OH) and dimethyl ether (CH3OCH3) are examples of geometric

isomers.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2, and 3

What is the charge on a nonmetallic, monatomic ion from Group 5A?

A.5+

B.1+

C.1″

D.3″

E.5″

What is the OH“ concentration of an aqueous solution with a pH of 2.77? (Kw = 1.01

10“14)

A.5.9 10“12 M

B.1.7 10“3 M

C.5.2 10“2 M

D.1.1 101 M

E.5.9 102 M

A precipitate will form when aqueous Pb(NO3)2 is added to an aqueous solution of

____.

A.Cu(NO3)2

B.NaI

C.NaCH3CO2

D.Pb(ClO4)2

E.KNO3

Which of the following statements concerning hybrid orbitals is/are CORRECT?

1/ The number of hybrid orbitals equals the number of atomic orbitals that are used to

create the hybrids.

2/ When atomic orbitals are hybridized, the s orbital and at least one p orbital are

always hybridized.

3/ To create tetrahedral structures, the s orbital and all three p orbitals must be

hybridized..

A.1 only

B.2 only

C.3 only

D.2 and 3

E.1, 2, and 3

Which of the following statements concerning semiconductors is/are CORRECT?

1/ The conduction of electricity in p-type semiconductors occurs by the movement of

electrons in the conduction band.

2/ Doping an intrinsic semiconductor, such as silicon, with a Group 3A element will

produce a p-type semiconductor.

3/ An n-type semiconductor uses the movement of positive holes in the valence band to

conduct electricity.

A.1 only

B.2 only

C.3 only

D.1 and 2

E.1, 2 and 3

A 1.850 g mixture of SrCO3 and SrO is heated. The SrCO3 decomposes to SrO and

CO2. What was the mass percentage of SrCO3 in the mixture if the mass after heating is

1.445 g?

A.26.6%

B.21.9%

C.13.7%

D.73.4%

E.78.1%

What color change is exhibited by phenolphthalein during a titration of aqueous acetic

acid with aqueous sodium hydroxide?

A.colorless to pink

B.pink to colorless

C.green to yellow

D.yellow to blue

E.blue to yellow

Which of the following sets of quantum numbers refers to a 4d orbital?

A.n = 2, = 1, = “1

B.n = 2, = 4, = “1

C.n = 4, = 2, = “1

D.n = 4, = 3, = 0

E.n = 4, = 3, = +2

Arrange the three common unit cells in order from least dense to most dense packing.

A.face-centered cubic < body-centered cubic < primitive cubic

B.primitive cubic < body-centered cubic < face-centered cubic

C.primitive cubic < face-centered cubic < body-centered cubic

D.body-centered cubic < primitive cubic < face-centered cubic

E.body-centered cubic < face-centered cubic < primitive cubic