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Write the most stable Lewis structure for each of the following compounds:

(a) Tetrafluoroethylene, C2F4. (The starting material for the preparation of Teflon)
(b) Acrylonitrile, C3H3N. The atoms are connected in the order CCCN, and all hydrogens are bonded to carbon. (The starting material for the preparation of acrylic fibers such as Orlon and Acrilan).
Examples of carbon-containing compounds include methane (CH4), chloromethane (CH3Cl), and methyl lithium (CH3Li). In which one does carbon bear the greatest partial positive charge? The greatest partial negative charge?
Like nitric acid, each of the following inorganic compounds will be frequently encountered in this text. Calculate the formal charge on each of the atoms in the Lewis structures given

(b) Sulfuric acid
(c) Nitrous acid
Verify that the formal charges on nitrogen in ammonium ion and boron in borohydride ion are as shown.
Use δ + and δ - notation to show the dispersal of charge to the hydrogens in NH4+ and BH4-
Expand the following condensed formulas so as to show all the bonds and unshared electron pairs.

(a) HOCH2CH2NH2
(b) (CH3)3CH
(c) ClCH2CH2Cl
(d) CH3CHCl2
(e) CH3NHCH2CH3
(f) (CH3)2CHCH=O
Expand the following bond-line representations to show all the atoms including carbon and hydrogen.
The figures are included in the solution.
There are many more isomers of CH3NO2 other than nitro methane and methyl nitrite. Some, such as Carbamic acid, an intermediate in the commercial preparation of urea for use as a fertilizer, are too unstable to isolate. Given the information that the nitrogen and both oxygens of Carbamic acid are bonded to carbon and that one of the carbon–oxygen bonds is a double bond, write a Lewis structure for Carbamic acid.
Write structural formulas for all the constitutionally isomeric compounds having the given molecular formula.

(b) C3H8O
(c) C4H10O
Electron delocalization can be important in ions as well as in neutral molecules. Using curved arrows, show how an equally stable resonance structure can be generated for each of the following anions:

4 figures of part a-d are included in the solution.
The salt sodium borohydride, NaBH4, has an ionic bond between Na+ and the anion BH4 - What are the H─B─H angles in the borohydride anion?
Specify the shape of the following:

(b) H4N+ (Ammonium ion)
(c) :N= N = N: (Azide Ion)
(d) CO32 - (Carbonate ion)
Which of the following compounds would you expect to have a dipole moment? If the molecule has a dipole moment, specify its direction.

(b) H2O
(c) CH4
(d) CH3Cl
(e) CH2O
(f) HCN
Construct an orbital diagram like that of Figure 1.20 for nitrogen in ammonia, assuming sp3 hybridization. In what kind of orbital is the unshared pair? What orbital overlaps are involved in the N─H bonds?
Describe the bonding in methylsilane (H3CSiH3), assuming that it is analogous to that of ethane. What is the principal quantum number of the orbitals of silicon that are hybridized?
Give the hybridization state of each carbon in the following Compounds:

(b) Formaldehyde (H2C=O)
(c) Ketene (H2 C=C=O)
(d) Propane (CH3CH=CH2)
(e) Acetone [(CH3)2C=O]
(f) Acrylonitrile (CH2=CHC ≡ CPN)
Each of the following species will be encountered at some point in this text. They all have the same number of electrons binding the same number of atoms and the same arrangement of bonds; they are isoelectronic. Specify which atoms, if any, bear a formal charge in the Lewis structure given and the net charge for each species.

(a) : N ≡ N:
(b) : C ≡ N:
(c) : C ≡ C:
(d) : N ≡ O:
(e) : C ≡ O:
You will meet all the following isoelectronic species in this text. Repeat the previous problem for these three structures.

(a) :Ö=C= Ö:
(b) :N = N = N :
(c) : Ö = N = O:
All the following compounds are characterized by ionic bonding between a group I metal cation and a tetrahedral anion. Write an appropriate Lewis structure for each anion, remembering to specify formal charges where they exist.

(a) NaBF4
(b) LiAIH4
(c) K2SO4
(d) Na3PO4
Determine the formal charge at all the atoms in each of the following species and the net charge on the species as a whole.

All figures for parts a-e are included in the solution.
What is the formal charge of oxygen in each of the following Lewis structures?
All Diagrams included in the Solution
Write a Lewis structure for each of the following organic molecules
All the Diagrams are included in the Solution
Write a structural formula for the CH3NO isomer characterized by the structural unit indicated. None of the atoms in the final structure should have a formal charge.
All the Diagrams are included in the Solution
Consider structural formulas A, B, and C:
All the Diagrams included in the Solution
Consider structural formulas A, B, C, and D:
All the Diagrams included in Solution
In each of the following pairs, determine whether the two represent resonance forms of a single species or depict different substances. If two structures are not resonance forms, explain why.
All the Diagrams included in the Solution
Among the following four structures, one is not a permissible resonance form. Identify the wrong structure. Why is it incorrect?
All the Diagrams included in the Solution
Keeping the same atomic connections and moving only electrons, write a more stable Lewis structure for each of the following. Be sure to specify formal charges, if any, in the new structure.
All the Diagrams included in the Solution
(a) Write a Lewis structure for sulfur dioxide in which the octet rule is satisfied for all three atoms. Show all electron pairs and include any formal charges. The atoms are connected in the order OSO.
(b) The octet rule may be violated for elements beyond the second period of the periodic table. Write a Lewis structure for sulfur dioxide in which each oxygen is connected to sulfur by a double bond. Show all electron pairs and formal charges.
Write structural formulas for all the constitutionally isomeric compounds having the given molecular formula.
(a) C4H10
(d) C4H9Br
(b) C5H12
(e) C3H9N
(c) C2H4Cl2
Write structural formulas for all the constitutional isomers of
(a) C3H8
(b) C3H6
(c) C3H4
Write structural formulas for all the constitutional isomers of molecular formula C3H6O that contain
(a) Only single bonds
(b) One double bond
For each of the following molecules that contain polar covalent bonds, indicate the positive and negative ends of the dipole, using the symbol v. Refer to Table 1.2 as needed.
(a) HCI
(c) HI
(e) HOCI
(b) ICI
(d) H2O
The compounds FCl and ICl have dipole moments μ that are similar in magnitude (0.9 and 0.7 D, respectively) but opposite in direction. In one compound, chlorine is the positive end of the dipole; in the other it is the negative end. Specify the direction of the dipole moment in each compound, and explain your reasoning.
Which compound in each of the following pairs would you expect to have the greater dipole moment μ? Why?
(a) NaCl or HCl
(e) CHCl3 or CCl3F
(b) HF or HClB
(f) CH3NH2 or CH3OH
(c) HF or BF3
(g) CH3NH2 or CH3NO2
(d) (CH3)3 or (CH3)3 CClS
Apply the VSEPR method to deduce the geometry around carbon in each of the following species:
(a):CH3
(b) CH3
(c) CH2
Expand the following structural representations so as to more clearly show all the atoms and any unshared electron pairs.:
All Diagrams included in the Solution File
Molecular formulas of organic compounds are customarily presented in the fashion C2H5BrO2. The numbers of carbon and hydrogen atoms are presented first, followed by the other atoms in alphabetical order. Give the molecular formulas corresponding to each of the compounds in the preceding problem. Are any of them isomers?
Select the compounds in Problem 1.43 in which all the carbons are
(a) sp3-hybridized
(b) sp2-hybridized do any of the compounds in Problem 1.43 contain an sp-hybridized carbon?
Account for all the electrons in each of the following species, assuming sp3 hybridization of the second-row element in each case. Which electrons are found in sp3-hybridized orbitals? Which are found in _ bonds?
(a) Ammonia (NH3)
(e) Borohydride anion (BH4 -)
(b) Water (H2O)
(f) Amide anion (: NH2)
(c) Hydrogen fluoride (HF)
(g) Methyl anion (: CH3)
(d) Ammonium ion (NH4 +)
Imagine describing the bonding in ammonia as arising by overlap of the half-filled unhybridized 2px, 2py, and 2pz orbitals of nitrogen with the half-filled 1s orbitals of three hydrogen atoms.
(a) What kind of orbital would the unshared pair occupy?
(b) What would you expect the bond angles to be?
Of the orbital overlaps shown in the illustration, one is bonding, one is ant bonding, and the third is nonbonding (neither bonding nor ant bonding). Which orbital overlap corresponds to which interaction? Why?
The element carbon has atomic number 6, and so it has a total of six electrons. Two of these electrons are in the 1s level. The four electrons in the 2s and 2p levels (the valence shell) are the valence electrons. Carbon has four valence electrons.
Referring to the periodic table as needed, write electron configurations for all the elements in the third period.
Which of the following ions possess a noble gas electron configuration?
(a) K+
(d) O-
(b) He+
(e) F-
(c) H-
(f) Ca2+
What is the electron configuration of C+? Of C−? Does either one of these ions have a noble gas (closed-shell) electron configuration?
Hydrogen is bonded to fluorine in hydrogen fluoride by a covalent bond. Write a Lewis formula for hydrogen fluoride.
Given the information that it has a carbon–carbon bond, write a satisfactory Lewis structure for C2H6 (ethane).
Many compounds contain more than one functional group. The structure of prostaglandin E1, a hormone that regulates the relaxation of smooth muscles, contains two different kinds of carbonyl groups. Classify each one (aldehyde, ketone, carboxylic acid, ester, amide, acyl chloride, or carboxylic acid anhydride).
An n-alkane of molecular formula C28H58 has been isolated from a certain fossil plant. Write a condensed structural formula for this alkane.
Much of the communication between insects involves chemical messengers called pheromones. A species of cockroach secretes a substance from its mandibular glands that alerts other cockroaches to its presence and causes them to congregate. One of the principal components of this aggregation pheromone is the alkane shown in the bond-line formula that follows. Give the molecular formula of this substance, and represent it by a condensed formula
Write condensed and bond-line formulas for the five isomeric C6H14 alkanes.
Refer to Table 2.4 as needed to answer the following questions:
(a) Beeswax contains 8–9% hentriacontane. Write a condensed structural formula for hentriacontane.
(b) Octacosane has been found to be present in a certain fossil plant. Write a condensed structural formula for octacosane.
Phytane is a naturally occurring alkane produced by the alga Spirogyra and is a constituent of petroleum. The IUPAC name for phytane is 2, 6, 10, 14-tetramethylhexadecane. Write a structural formula for phytane.
Derive the IUPAC names for
(a) The isomers of C4H10 (c) (CH3)3CCH2CH (CH3)2
(b) The isomers of C5H12 (d) (CH3)3CC (CH3)3
Give the structures and IUPAC names of all the C5H11 alkyl groups, and identify them as primary, secondary, or tertiary alkyl groups, as appropriate.
Give an acceptable IUPAC name for each of the following
Alkanes:
(a) CH2 CH3
CH3CH2CHCHCHCH2CHCH3
CH3 CH3 CH3
(b) (CH3CH2)2CHCH2CH (CH3)2
(c) CH3
CH3CH2CHCH2CHCH2CHCH (CH3)2
CH2CH3 CH2CH (CH3)2
Name each of the following compounds:
Match the boiling points with the appropriate alkanes.
Alkanes: octane, 2-methylheptane, 2, 2, 3, 3-tetramethylbutane, nonane
Boiling points (°C, 1 atm): 106, 116, 126, 151
Write a balanced chemical equation for the combustion of cyclohexane.
Using the data in Table 2.5, estimate the heat of combustion of
(a) 2-Methylnonane (in kcal/mol)
(b) Icosane (in kJ/mol)
Without consulting Table 2.5 arrange the following compounds in order of decreasing heat of combustion: pentane, isopentane, neopentane, hexane.
The reactions shown will all be encountered in Chapter 6. Classify each according to whether it proceeds by oxidation of carbon, by reduction of carbon, or by a process other than oxidation–reduction.
(a) CH2 = oeCH2 + H2O → CH3CH2OH
(b) CH2 = oeCH2 + Br2 → BrCH2CH2Br
(c) 6CH2 = oeCH2 + B2H6 → 2(CH3CH2)3B
Write structural formulas, and give the IUPAC names for the nine alkanes that have the molecular formula C7H16.
From among the 18 constitutional isomers of C8H18, write structural formulas, and give the IUPAC names for those that are named as derivatives of
(a) Heptane (c) Pentane
(b) Hexane (d) Butane
Write a structural formula for each of the following compounds:
(a) 6-Isopropyl-2, 3-dimethylnonane (e) Cyclobutylcyclopentane
(b) 4-tert-Butyl-3-methylheptane (f) (2, 2-Dimethylpropyl) cyclohexane
(c) 4-Isobutyl-1, 1-dimethylcyclohexane (g) Pentacosane
(d) sec-Butylcycloheptane (h) 10-(1-methylpentyl) pentacosane
Give the IUPAC name for each of the following compounds:
(a) CH3 (CH2)25CH3
(b) (CH3)2CHCH2 (CH2)14CH3
(c) (CH3CH2)3CCH (CH2CH3)2
All the parts of this problem refer to the alkane having the carbon skeleton shown.
Give the IUPAC name for each of the following alkyl groups, and classify each one as primary, secondary, or tertiary:
(a) CH3 (CH2)10CH2± (b) ±CH2CH2CHCH2CH2CH3 W CH2CH3
Pristane is an alkane that is present to the extent of about 14% in shark liver oil. Its IUPAC name is 2, 6, 10, 14-tetramethylpentadecane. Write its structural formula.
Hectane is the IUPAC name for the unbranched alkane that contains 100 carbon atoms.
(a) How many _ bonds are there in hectane?
(b) How many alkanes have names of the type x-methylhectane?
(c) How many alkanes have names of the type 2, x-dimethylhectane?
Which of the compounds in each of the following groups are isomers?
(a) Butane, cyclobutane, isobutane, 2-methylbutane
(b) Cyclopentane, neopentane, 2, 2-dimethylpentane, 2, 2, 3-trimethylbutane
(c) Cyclohexane, hexane, methylcyclopentane, 1, 1, 2-trimethylcyclopropane
(d) Ethylcyclopropane, 1, 1-dimethylcyclopropane, 1-cyclopropylpropane, Cyclopentane
(e) 4-Methyltetradecane, 2, 3, 4, 5-tetramethyldecane, pentadecane,
4-cyclobutyldecane
Epichlorohydrin is the common name of an industrial chemical used as a component in epoxy cement. The molecular formula of epichlorohydrin is C3H5ClO. Epichlorohydrin has an epoxide functional group; it does not have a methyl group. Write a structural formula for epichlorohydrin.
(a) Complete the structure of the pain-relieving drug ibuprofen on the basis of the fact that ibuprofen is a carboxylic acid that has the molecular formula C13H18O2, X is an isobutyl group, and Y is a methyl group.
Isoamyl acetate is the common name of the substance most responsible for the characteristic odor of bananas. Write a structural formula for isoamyl acetate, given the information that it is an ester in which the carbonyl group bears a methyl substituent and there is a 3-methylbutyl group attached to one of the oxygens.
N-Butyl mercaptan is the common name of a foul-smelling substance obtained from skunk fluid. It is a thiol of the type RX, where R is an n-butyl group and X is the functional group that characterizes a thiol. Write a structural formula for this substance.
Some of the most important organic compounds in biochemistry are the _-amino acids, represented by the general formula shown.
Uscharidin is the common name of a poisonous natural product having the structure shown.
Locate all of the following in uscharidin:
Write the structural formula of a compound of molecular formula C4H8Cl2 in which
(a) All the carbons belong to methylene groups
(b) None of the carbons belong to methylene groups
Female tiger moths signify their presence to male moths by giving off a sex attractant. The sex attractant has been isolated and found to be a 2-methyl-branched alkane having a molecular weight of 254. What is this material?
Write a balanced chemical equation for the combustion of each of the following compounds:
(a) Decane (c) Methylcyclononane
(b) Cyclodecane (d) Cyclopentylcyclopentane
The heats of combustion of methane and butane are 890 kJ/mol (212.8 kcal/mol) and 2876 kJ/mol (687.4 kcal/mol), respectively. When used as a fuel, would methane or butane generate more heat for the same mass of gas? Which would generate more heat for the same volume of gas?
In each of the following groups of compounds, identify the one with the largest heat of combustion and the one with the smallest. (Try to do this problem without consulting Table 2.5.)
(a) Hexane, heptane, octane
(b) Isobutane, pentane, isopentane
(c) Isopentane, 2-methylpentane, neopentane
(d) Pentane, 3-methylpentane, 3, 3-dimethylpentane
(e) Ethylcyclopentane, ethylcyclohexane, ethylcycloheptane
(a) Given ΔH° for the reaction
H2 (g) + ½ O2 (g) → H2O (l) ΔH° = -286 kJ
Along with the information that the heat of combustion of ethane is 1560 kJ/mol and that of ethylene is 1410 kJ/mol, calculate ΔH° for the hydrogenation of ethylene:
CH2 = CH2 (g) + H2 (g) → CH3CH3 (g)
(b) If the heat of combustion of acetylene is 1300 kJ/mol, what is the value of ΔH° for its hydrogenation to ethylene? To ethane?
(c) What is the value of ΔH° for the hypothetical reaction
2CH2 = CH2 (g) → CH3CH3 (g) _ HC + PCH (g)
Each of the following reactions will be encountered at some point in this text. Classify each one according to whether the organic substrate is oxidized or reduced in the process.
(a) CH3C = PCH + 2Na + 2NH3 → CH3CH = CH2 _ 2NaNH2
The reaction shown is important in the industrial preparation of dichlorodimethylsilane for eventual conversion to silicone polymers.
2CH3Cl + Si → (CH3)2SiCl2
Is carbon oxidized, or is it reduced in this reaction?
Compound A undergoes the following reactions:
(a) To what class of compounds does compound A belong?
(b) Which of the reactions shown require(s) an oxidizing agent?
(c) Which of the reactions shown require(s) a reducing agent?
(d) Identify the class to which each of the reaction products belongs.
Each of the following equations describes a reaction of a compound called methyl formate. To what class of compounds does methyl formate belong? Which reactions require a reducing agent? Which require an oxidizing agent? Which reactions are not oxidation–reduction?
Which atoms in the following reaction undergo changes in their oxidation state? Which atom is oxidized? Which one is reduced?
2CH3CH2OH + 2Na → 2CH3CH2ONa + H2
We have not talked about heats of combustion of compounds other than hydrocarbons. Nevertheless, from among the compounds shown here, you should be able to deduce which one gives off the most heat on combustion (to give CO2 and H2O) and which one the least.
CH3CH2OH HOCH2CH2OH HOC – COH
Identify the alkanes corresponding to each of the drawings shown.
Find the conformations in Figure 3.4 in which the red circles are
(a) Gauche and
(b) Anti.
Sketch a potential energy diagram for rotation around a carbon–carbon bond in propane. Clearly identify each potential energy maximum and minimum with a structural formula that shows the conformation of propane at that point. Does your diagram more closely resemble that of ethane or of butane? Would you expect the activation energy for bond rotation in propane to be more than or less than that of ethane? Of butane?
Given the following partial structure, add a substituent X to C-1 so that it satisfies the indicated stereo chemical requirement. You may find it helpful to build a molecular model for reference.
(a) Anti to A
(c) Anti to C-3
(b) Gauche to A
(d) Gauche to C-3
The following questions relate to a cyclohexane ring depicted in the chair conformation shown.
(a) Is a methyl group at C-6 that is “down” axial or equatorial?
(b) Is a methyl group that is “up” at C-1 more or less stable than a methyl group that is up at C-4?
(c) Place a methyl group at C-3 in its most stable orientation. Is it up or down?
Draw or construct a molecular model of the most stable conformation of 1-tert-butyl-1-methylcyclohexane.
The heats of combustion of ethylcyclopropane and methylcyclobutane have been measured as 3352 and 3384 kJ/mol (801.2 and 808.8 kcal/mol), respectively. Assign the correct heat of combustion to each isomer.
Exclusive of compounds with double bonds, four hydrocarbons are constitutional isomers of cis- and trans-1, 2-dimethylcyclopropane. Identify these compounds.
Based on what you know about disubstituted cyclohexanes, which of the following two stereoisomeric 1, 3, 5-trimethylcyclohexanes would you expect to be more stable?
Write structural formulas or make molecular models for the most stable conformation of each of the following compounds:
(a) trans-1-tert-Butyl-3-methylcyclohexane
(b) cis-1-tert-Butyl-3-methylcyclohexane
(c) trans-1-tert-Butyl-4-methylcyclohexane
(d) cis-1-tert-Butyl-4-methylcyclohexane
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