CEM 562 Midterm 2 | Course Paper

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Using the following bond energies:

BondBond Energy (kJ/mol)

CºC839

C−H413

O=O495

C=O799

O−H467

estimate the heat of combustion for one mole of acetylene:

C2H2(g) + O2(g) –> 2CO2(g) + H2O(g)

A)1228 kJ

B)−1228 kJ

C)−447 kJ

D)+447 kJ

E)+365 kJ

Using the following electronegativity values:

C2.5Cl3.0

H2.1O3.5

select from the following group the molecule that fits the given statement:

a)CH3CHO

b)CO2

c)CH3Cl

d)C2H6

e)none

This molecule contains a carbon atom with trigonal planar geometry.

A)CH3CHO

B)CO2

C)CH3Cl

D)C2H6

E)none of these

Draw the Lewis structures of the molecules below and use them to answer the

following questions:

I.BH3

II.NO2

III.SF6

IV.O3

V.PCl5

Which of these molecules show resonance?

A)I, II

B)II, IV

C)II, V

D)III, IV

E)III, V

Consider the molecule and the following hybridization choices:

What is the hybridization of the carbon atom that is double-bonded to oxygen?

A)sp

B)sp2

C)sp3

D)dsp3

E)d2sp3

A certain substance has the phase diagram shown below. At which of the following

values of T and P is the substance a pure liquid?

A)T = 80C, P = 1 atm

B)T = 100C, P = 0.5 atm

C)T = 700C, P = 1.2 atm

D)T = 800C, P = 1 atm

E)T = 100C, P = 1 atm

Which of the following compounds is expected to have the HIGHEST melting point?

A)CH3OCH3

B)CH3CH2OH

C)CH3CH2CH2CH3

D)CH3CH2CH3

E)CH3Cl

Consider the representations below to answer the next three questions.

(I)

(II)

(III)

Which drawing best represents the interactions in a sample of HF?

A)I

B)II

C)III

D)I, II

E)all of the above

The following questions refer to the gas-phase decomposition of ethylene chloride.

C2H5Cl –> products

Experiment shows that the decomposition is first order.

The following data show kinetics information for this reaction:

What is the half-life time for this reaction?

A)0.7 s

B)1.3 s

C)8.9 s

D)6.3 s

E)2.2 s

Complete the following reaction in aqueous solution and select the spectator ions,

Fe(NO3)2+ (NH4)2CO3 –>

A)Fe2+(aq), NO3

–(aq)

B)NH4

+(aq), NO3

–(aq)

C)NH4

+(aq), CO3

2-(aq)

D)Fe2+(aq), NH4

+(aq), NO3

–(aq), CO3

2-(aq)

E)Fe2+(aq), CO3

2-(aq)

Balance the following redox equation in acidic solution. What is the coefficient of the

H+ion? MnO4

–(aq) + H2O2(aq) –> Mn2+(aq) + O2(g)

A) 2

B) 4

C) 6

D) 8

E) 16

Which of the following pairs of 0.100 mol L-1solutions, when mixed, will produce a

buffer solution?

A) 50 mL of aqueous CH3COONa and 25 mL aqueous NaOH

B) 50 mL of aqueous CH3COOH and 25 mL aqueous HCl

C) 50 mL of aqueous CH3COOH and 25 mL aqueous CH3COONa

D) 50 mL of aqueous CH3COOH and 100 mL aqueous NaOH

E) 50 mL of aqueous NaOH and 25 mL aqueous HCl

Which of the following has a different value on the moon compared to earth?

A)mass C)time

B)weight D)moles

Given the following Lewis structure:

How many unshared pairs of electrons are present in this molecule?

A)0

B)1

C)2

D)3

E)4

Which of the following reactions is possible at the anode of a galvanic cell?

A) Zn –> Zn2++ 2e–

B) Zn2++ 2e––> Zn

C) Zn2++ Cu –> Zn + Cu2+

D) Zn + Cu2+–> Zn2++ Cu

E) two of these

Calculate the value of where

A)2.2 L/mol·s

B)0.75 L/mol·s

C)1.9 L/mol·s

D)0.21 L/mol·s

E)none of these

Use the bond energies given below to calculate the enthalpy change for the reaction,

HCN(g) + 2 H2(g) ® CH3NH2(g)

BondBond Energy (kJ/mol)BondBond Energy (kJ/mol)

H-H432C-H413

C-N305C=N615

C:N891N-H391

A)-590 kJ

B)-158 kJ

C)+18 kJ

D)+133 kJ

E)+158 kJ

Consider the reaction, which is exothermic as written, PCl5(g) PCl3(g) + Cl2(g).

Which of the following changes would result in the production of MORE Cl2(g)?

I.adding PCl3(g)

II.removing PCl3(g)

III.reducing the volume of the container

IV.removing PCl5(g)

V.increasing the temperature

VI.increasing the volume of the container

VII.adding PCl5(g)

VIII.reducing the temperature

IX.adding a suitable catalyst

A) I, IV, V, VI

B) II, VI, VII, VIII

C) II, III, VII, VIII

D) II, V, VI, VII

E) II, VI, VII, VIII, IX

How many molecules of sucrose (table sugar), C12H22O11, dissolved in 450.0 g of

water are needed to make a 1.81m solution?

Complete the following table.

For the reaction , the following data were collected:

The concentration of O2at t = 10. minutes is

Larger atomic radius, P or Sb

Calculate the osmotic pressure (in torr) of 6.00 L of an aqueous 0.958 M solution at

30.0C, if the solute concerned is totally ionized into three ions (e.g., it could be

Na2SO4or MgCl2).

For each of the following compounds:

a)Draw the Lewis structure.

b)Give the shape of the molecule.

c)Indicate the polarity of the molecule.

AlF3

The calcium atom is much larger than the calcium ion, while the fluorine atom is much

smaller than the fluorine ion. Explain this natural occurrence.

A cation has a larger proton to electron ratio than the corresponding neutral atom, so the

remaining electrons are more closely held. An anion has a smaller proton to electron

ratio than its corresponding neutral atom, so the electrons can not be held as closely.

Consider the graph below to answer the next two questions:

Explain why argon has the highest ionization energy.

Which of the following ligands are capable of linkage isomerism?

Larger atomic or ionic radius, Mg or Mg2+