Chem 93421 | Course Paper

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What is the pH of 0.010 M aqueous hypochlorous acid? (Ka of HOCl = 3.5 10“8)

A.2.00

B.4.50

C.4.73

D.6.54

E.7.45

A statement of the first law of thermodynamics is that

A.in a spontaneous process, the entropy of the universe increases.

B.there is no disorder in a perfect crystal at 0 K.

C.the total energy of the universe is always decreasing.

D.the total energy of the universe is constant.

E.mass and energy are conserved in all chemical reactions.

At a given temperature, 0.0664 mol N2O4(g) is placed in a 1.00 L flask. After reaching

equilibrium, the concentration of NO2(g) is 6.1 10“3 M. What is Kc for the reaction

below?

N2O4(g) 2 NO2(g)

A.3.7 10“5

B.1.4 10“4

C.5.9 10“4

D.9.6 10“2

E.1.8 103

Use VSEPR theory to predict the molecular geometry around the nitrogen atom in

nitrite ion, NO2

“.

A.trigonal-planar

B.tetrahedral

C.trigonal-pyramidal

D.T-shaped

E.bent

Which one of the following molecules has the lowest boiling point?

A.CH4

B.CHCl3

C.CH2Cl2

D.CH3Cl

E.CCl4

Low density polyethylene (LDPE) is most likely to be used in

A.sandwich bags.

B.bottle caps.

C.rigid pipes.

D.contact lenses.

E.fabrics and apparel.

C2H2F4 is the formula for two possible molecules. C2H2F4 is an example of a(n)

A.structural formula.

B.empirical formula.

C.condensed formula.

D.space-filling model.

E.molecular formula.

The Henry’s law constant for O2 in water at 25 C is 1.3 10“3 mol/kgbar. What partial

pressure of O2 (in atm) is necessary to achieve an equilibrium concentration of 2.9 10“3

mol/kg O2? (1 atm = 0.9869 bar)

A.0.44 atm

B.0.45 atm

C.2.1 atm

D.2.3 atm

E.3.8 atm

If a nucleus undergoes beta particle emission

A.its atomic number decreases by four and its mass number decreases by two.

B.its atomic number decreases by two and its mass number decreases by four.

C.its atomic number increases by one and its mass number is unchanged.

D.its atomic number decreases by one and its mass number increases by one.

E.its atomic number is unchanged and its mass number decreases by one.

Calculate the density (in g/L) of CH4(g) at 75 C and 2.1 atm. (R = 0.08206 Latm/molK)

A. 0.18 g/L

B.0.85 g/L

C.1.2 g/L

D.3.2 g/L

E.5.5 g/L

All of the following complexes will be colored (in the visible) EXCEPT ____.

A.[Co(en)3]2+

B.[Fe(CN)6]4″

C.[Ni(H2O)6]2+

D.[Sc(NH3)6]3+

E.[Cu(NH3)4]2+

Which equation represents the number of atoms in a face-centered cubic unit cell?

The building block of silicate minerals is the

A.linear SiO unit.

B.the bent SiO2 unit.

C.trigonal-bipyramidal SiO5 unit.

D.tetrahedral SiO4 unit.

E.the linear SiO2 unit.

What is the molar mass of calcium chloride hexahydrate?

A.75.53 g/mol

B.111.0 g/mol

C.117.0 g/mol

D.183.6 g/mol

E.219.1 g/mol

Aspirin is produced by the reaction of salicylic acid (M = 138.1 g/mol) and acetic

anhydride (M = 102.1 g/mol).

C7H6O3(s) + C4H6O3( ) C9H8O4(s) + C2H4O2( )

If 2.04 g of C9H8O4 (M = 180.2 g/mol) is produced from the reaction of 3.03 g C7H6O3

and 4.01 g C4H6O3, what is the percent yield?

A.28.8%

B.29.0%

C.50.9%

D.51.6%

E.67.3%

What is the oxidation number of sulfur in sulfur in H2S?

A.”2

B.0

C.+2

D.+4

E.+6

Which of the following statements regarding subshell filling order for a neutral atom

is/are CORRECT?

1/ Electrons are assigned to the 4f subshell before they are assigned to the 6s subshell.

2/ Electrons are assigned to the 5d subshell before they are assigned to the 6p subshell.

3/ Electrons are assigned to the 4p subshell before they are assigned to the 4s subshell.

A.1 only

B.2 only

C.3 only

D.1 and 3

E.1, 2, and 3

How many neutrons are in an atom of gallium-71?

A.71

B.40

C.111

D.31

E.102

Predict the formula of the product of a reaction of silicon and oxygen.

A.SiO

B.SiO2

C.Si2O3

D.SiO3

E.SiO4

An unknown hydrocarbon contains carbon, hydrogen, and oxygen. Combustion of

1.5000 g of the hydrocarbon produces 1.1738 g H2O and 2.1505 g CO2. What is the

empirical formula of the hydrocarbon?

A.CHO

B.C2H3O

C.C3H4O

D.C3H8O3

E.C5H5O

The rate constant of a first-order decomposition reaction is 0.0147 s“1. If the initial

concentration of reactant is 0.178 M, what is the concentration of reactant after 30.0

seconds?

A.8.72 105 M

B.0.0645 M

C.0.115 M

D.0.0785 M

E.0.643 M

Which of the following statements is INCORRECT?

A.Phosphoric acid gives a tart taste to carbonated beverages such as colas.

B.Sodium phosphate, Na3PO4, is a relatively strong base used in paint strippers.

C.Ca(H2PO4)2H2O is used as an acid leavening agent in baking powder.

D.Ca3(PO4)2 is a dark green compound used in latex paints.

E.Calcium monohydrogen phosphate is an abrasive and polishing agent in toothpaste.

When 0.20 mole HF is dissolved in water to a volume of 1.00 L, 5.8% of the HF

dissociates to form F“(aq). What is the equilibrium constant for the reaction?

HF(aq) + H2O( ) F“(aq) + H3O+(aq)

A.1.3 10“4

B.7.1 10“4

C.1.2 10“2

D.1.7 10“2

E.6.2 10“2

What is the pH of 0.30 M aqueous formic acid? (Ka of HCO2H = 1.8 10“4)

A.0.52

B.1.61

C.2.14

D.3.74

E.4.24

Write a balanced reaction for the decay of barium-127 by positron emission.

For a nonmetal in Group 6A of the periodic table, the most common monatomic ion

will have a charge of ____.

A.3″

B.2″

C.1″

D.1+

E.2+

All of the following statements concerning nuclei are true EXCEPT

A.only hydrogen-1 and helium-3 have more protons than neutrons.

B.from He to Ca, stable nuclei have roughly equal numbers of protons and neutrons.

C.elements with odd atomic numbers have more stable isotopes than do those with even

atomic numbers.

D.the neutron to proton ratio in stable nuclei increases as mass increases.

E.more stable isotopes have an even number of neutrons than an odd number.

Which of the following substances is never a Brnsted-Lowry base in an aqueous

solution?

A.potassium hydroxide, NaOH(g)

B.sodium hydrogen phosphate, Na2HPO4(s)

C.sodium phosphate, Na3PO4(s)

D.ammonium chloride, NH4Cl(g)

E.sodium bicarbonate, NaHCO3(s)

The following reaction occurs spontaneously.

2 H+(aq) + Ca(s) Ca2+(aq) + H2(g)

Write the balanced oxidation half-reaction.

A.2 H+(aq) + 2 e“ H2(g)

B.2 H+(aq) H2(g) + 2 e“

C.H2(g) 2 H+(aq) + 2 e“

D.Ca(s) + 2 e“ Ca2+(aq)

E.Ca(s) Ca2+(aq) + 2 e“

What two of the following elements or compounds are used to reduce Fe2O3 to Fe in a

blast furnace?

A.H2(g) and C(s)

B.Cl2(g) and CO2(g)

C.C(s) and CO(g)

D.CaSiO3(s) and CaO(s)

E.CO2(g) and CaO(s)

Which of the following is the smallest mass?

A.1.5 108 pg

B.1.5 106 ng

C.1.5 103 mg

D.1.5 10“1 mg

E.1.5 10“5 g