Chapter 26

Write structural formulas corresponding to these condensed formulas. (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCHBrCH}_{3}\) (b) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\) (c) \(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{CHCH}=\mathrm{CHCH}_{2} \mathrm{CH}_{3}\).

Draw a structural formula for each of the following compounds. (a) 3 -isopropyloctane; (b) 2 -chloro- 3 -methylpentane; (c) 2 -pentene; (d) dipropyl ether.

Supply a structural formula for each of the following compounds. (a) 1,3,5 -trimethylbenzene; (b) \(p\) -nitrophenol; (c) 3 -amino- 2,5 -dichlorobenzoic acid (a plant-growth regulator).

Write structural formulas corresponding to these condensed formulas. (a) \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\) (b) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CH}_{2} \mathrm{Br}\) (c) \(\mathrm{Cl}_{3} \mathrm{CCH}_{2} \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{Cl}\).

Draw Lewis structures of the following simple organic molecules: (a) \(\mathrm{CH}_{3} \mathrm{CHClCH}_{3} ;\) (b) \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}\) (c) \(\mathrm{CH}_{3} \mathrm{CHO}\).

Draw Lewis structures of the following simple organic molecules: (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH} ;\) (b) \(\mathrm{H}_{3} \mathrm{CCN}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}\).

With appropriate sketches, represent chemical bonding in terms of the overlap of hybridized and unhybridized atomic orbitals in the following molecules. (a) \(\mathrm{C}_{4} \mathrm{H}_{10} ;\) (b) \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CHCl} ;\) (c) \(\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CH}\).

Draw structural formulas for all the isomers of \(\mathrm{C}_{7} \mathrm{H}_{16}\).

Draw and name all the isomers of (a) \(\mathrm{C}_{6} \mathrm{H}_{14}\) (b) \(\mathrm{C}_{4} \mathrm{H}_{8} ;\) (c) \(\mathrm{C}_{4} \mathrm{H}_{6}\). [Hint: Do not forget double bonds, rings, and combinations of these.].

Identify the functional group in each compound (i.e., alcohol, amine, etc.). (a) \(\mathrm{CH}_{3} \mathrm{CHBrCH}_{2} \mathrm{CH}_{3}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{CHO}\) (c) \(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{CH}_{3}\) (d) \(\mathrm{C}_{6} \mathrm{H}_{4}(\mathrm{OH})_{2}\).

Identify the functional group in each compound (i.e., alcohol, amine, etc.). (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}\) (b) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{OCH}_{3}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}\left(\mathrm{NH}_{2}\right) \mathrm{CH}_{2} \mathrm{CH}_{3}\) (d) \(\mathrm{CH}_{3} \mathrm{COOCH}_{3}\).

The functional groups in each of the following pairs have certain features in common, but what is the essential difference between them? (a) carbonyl and carboxyl (b) aldehyde and ketone (c) acetic acid and acetyl group

By name or formula, give one example of each of the following types of compounds: (a) aromatic nitro compound; (b) aliphatic amine; (c) chlorophenol; (d) aliphatic diol; (e) unsaturated aliphatic alcohol; (f) alicyclic ketone; (g) halogenated alkane; (h) aromatic dicarboxylic acid.

Give the isomers of \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\) that are ethers.

Give the isomers of \(C_{5} \mathrm{H}_{12} \mathrm{O}\) that are ethers.

Give the isomers of the carboxylic acid with molecular formula \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}\).

Give the isomers of the carboxylic acid with the molecular formula \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}\).

Give the isomers of the esters having the molecular formula \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}\).

Give the isomers of the esters having the molecular formula \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}\).

Give the noncyclic isomers with molecular formula \(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}\) that contain more than one functional group.

Give the isomers with molecular formula \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}\) that contain more than one functional group.

Give an acceptable name for each of the following structures. (a) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{C}\left(\mathrm{CH}_{3}\right)_{3}\) (b) \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{C}=\mathrm{CH}_{2}\) (c) \(\mathrm{CH}_{3}-\mathrm{CH}-\mathrm{CH}-\mathrm{CH}_{3}\) \(\mathrm{CH}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CCH}\left(\mathrm{CH}_{3}\right)_{2}\) (e) \(\mathrm{CH}_{3} \mathrm{CH}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right) \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{CH}_{3}\) (f) \(\mathrm{CH}_{3} \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}\left(\mathrm{CH}_{3}\right) \mathrm{CCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}=\mathrm{CH}_{2}\)

Draw a condensed structure to correspond to each of the following names. (a) methylbutane; (b) cyclohexene; (c) 2 -methyl- 3 -hexyne; (d) 2 -butanol; (e) ethyl isopropyl ether; (f) propanal

Does each of the following names convey sufficient information to suggest a specific structure? Explain. (a) pentene; (b) butanone; (c) butyl alcohol; (d) methylaniline; (e) methylcyclopentane; (f) dibromobenzene

Indicate why each of these names is incorrect, and give a correct name. (a) 3 -pentene; (b) pentadiene; (c) 1-propanone; (d) bromopropane; (e) 2,6 -dichlorobenzene; (f) 2 -methyl- 3 -pentyne

Supply condensed structural formulas for the following substances. (a) 2,4,6 -trinitrotoluene (TNT-an explosive) (b) methyl salicylate (oil of wintergreen) [Hint: Salicylic acid is \(o \text { -hydroxybenzoic acid. }]\) (c) 2 -hydroxy-1,2,3-propanetricarboxylic acid (citric \(\left.\operatorname{acid}, \mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{7}\right)\).

Supply condensed structural formulas for the following substances. (a) \(o\) -tert-butylphenol (an antioxidant in aviation gasoline) (b) 1 -phenyl- 2 -aminopropane (benzedrine-an amphetamine, ingredient in "pep pills") (c) 2 -methylheptadecane (a sex pheromone of tiger moths-a chemical used for communication among members of the species) [ Hint: Heptadeca means 17.].

Classify the carbon atoms in (a) methylbutane, and (b) 2,2 -dimethylpropane as methyl, primary \(\left(1^{\circ}\right)\) secondary \(\left(2^{\circ}\right),\) tertiary \(\left(3^{\circ}\right),\) or quaternary \(\left(4^{\circ}\right)\).

Classify the carbon atoms in (a) 2,4 -dimethylpentane, and (b) ethylcyclobutane as methyl, primary \(\left(1^{\circ}\right)\) secondary \(\left(2^{\circ}\right),\) tertiary \(\left(3^{\circ}\right),\) or quaternary \(\left(4^{\circ}\right)\).

Draw Newman projections for the staggered and eclipsed conformations of pentane for rotation about the \(\mathrm{C} 2-\mathrm{C} 3\) bond. Which conformation is lowest in energy?

Draw Newman projections for the staggered and eclipsed conformations of 2 -methylpentane for rotation about the \(\mathrm{C} 2-\mathrm{C} 3\) bond. Which conformation is lowest in energy?

For each of the following substituted cyclohexanes, draw the two possible chair conformations, label each substituent as axial or equatorial, and identify the more stable conformer. (a) cyclohexanol (b) trans-3-methylcyclohexanol

For each of the following substituted cyclohexanes, draw the two possible chair conformations, label each substituent as axial or equatorial, and identify the more stable conformer. (a) cis-1-isopropyl-3-methylcyclohexane (b) \(c\) is- 4 -tert-butylcyclohexanol

Why is it not necessary to refer to ethene and propene as 1 -ethene and 1 -propene? Can the same be said for butene?

Alkenes (olefins) and cyclic alkanes (alicyclics) each have the generic formula \(\mathrm{C}_{n} \mathrm{H}_{2 n}\). In what important ways do these types of compounds differ structurally?

Draw the \(E\) and \(Z\) isomers of (a) 2 -chloro-2-butene; (b) 3 -methyl- 2 -pentene.

Draw the \(E\) and \(Z\) isomers of (a) 3 -methyl- 3 -hexene; \((b)\) 3-fluoro-2-methyl-3-hexene.

Supply a name or structural formula for each of the following. (a) phenylacetylene (b) \(m\) -dichlorobenzene

Supply a name or structural formula for each of the following. (a) \(p\) -phenylphenol (b) 3 -hydroxy- 4 -isopropyltoluene (thymol- -flavor constituent of the herb thyme)

Draw the structure for each of the following. (a) \((Z)-1,3,5\) -tribromo- 2 -pentene (b) \((E)-1,2\) -dibromo- 3 -methyl- 2 -hexene (c) (S)-1-bromo-1-chlorobutane (d) \((R)-1,3\) -dibromohexane (e) (S)-1-chloro-2-propanol.

Draw the structure for each of the following. (a) \((R)-1\) -bromo-1-chloroethane (b) ( \(E\) )-2-bromo-2-pentene (c) \((Z)-1-\) chloro- 3 -ethyl- 3 -heptene (d) \((R)\) -2-hydroxypropanoic acid (e) ( \(S\) )-2-aminopropanoate anion.

Consider the following molecular formulas. How many elements of unsaturation are there in each case? (a) \(\mathrm{C}_{4} \mathrm{H}_{11} \mathrm{N} ;\) (b) \(\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O} ;\) (c) \(\mathrm{C}_{9} \mathrm{H}_{15} \mathrm{ClO}\).

Consider the following molecular formulas. How many elements of unsaturation are there in each case? (a) \(\mathrm{C}_{5} \mathrm{H}_{9} \mathrm{NO}\) (b) \(\mathrm{C}_{5} \mathrm{H}_{8} \mathrm{O}_{3} ;\) (c) \(\mathrm{C}_{5} \mathrm{H}_{9} \mathrm{ClO}\).

Draw as many structural isomers as you can for cyclic ethers (no - OH groups) having the formula \(\mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}\) Try to draw at least six. (There are more than six.).

Supply condensed or structural formulas for the following substances. (a) 1,5 -cyclooctadiene (an intermediate in the manufacture of resins) (b) 3,7,11 -trimethyl- 2,6,10 -dodecatriene- 1 -ol (farnesol \(-\) odor of lily of the valley) [Hint: Dodeca means \(12 .]\) (c) 2,6 -dimethyl- 5 -hepten- 1 -al (used in the manufacture of perfume).

The symbol: is often used to represent benzene. It is also the structural formula of cyclohexatriene. Are benzene and cyclohexatriene the same substance? Explain.

Use the half-reaction method to balance the following redox equations. (a) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}+\mathrm{Fe}+\mathrm{H}^{+} \longrightarrow\) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{3}^{+}+\mathrm{Fe}^{3+}+\mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OH}+\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}+\mathrm{H}^{+} \longrightarrow\) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CO}_{2} \mathrm{H}+\mathrm{Cr}^{3+}+\mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CH}_{2}+\mathrm{MnO}_{4}^{-}+\mathrm{H}_{2} \mathrm{O} \longrightarrow\) \(\mathrm{CH}_{3} \mathrm{CHOHCH}_{2} \mathrm{OH}+\mathrm{MnO}_{2}+\mathrm{OH}^{-}\).

A \(10.6 \mathrm{g}\) sample of benzaldehyde was allowed to react with \(5.9 \mathrm{g} \mathrm{KMnO}_{4}\) in an excess of \(\mathrm{KOH}(\mathrm{aq}) .\) After filtration of the \(\mathrm{MnO}_{2}(\mathrm{s})\) and acidification of the solution, \(6.1 \mathrm{g}\) of benzoic acid was isolated. What was the percent yield of the reaction? [ Hint: Write half-equations for the oxidation and reduction half-reactions.

Combustion of a \(0.1908 \mathrm{g}\) sample of a compound gave \(0.2895 \mathrm{g} \mathrm{CO}_{2}\) and \(0.1192 \mathrm{g} \mathrm{H}_{2} \mathrm{O} .\) Combustion of a second sample weighing \(0.1825 \mathrm{g}\) yielded \(40.2 \mathrm{mL}\) of \(\mathrm{N}_{2}(\mathrm{g}),\) collected over \(50 \% \mathrm{KOH}(\mathrm{aq})\) (vapor pressure \(=\) \(9 \mathrm{mmHg}\) ) at \(25^{\circ} \mathrm{C}\) and \(735 \mathrm{mm} \mathrm{Hg}\) barometric pressure. When \(1.082\mathrm{g}\) of compound was dissolved in \(26.00 \mathrm{g}\) benzene \(\left(\mathrm{mp} 5.50^{\circ} \mathrm{C}, K_{\mathrm{f}}=5.12^{\circ} \mathrm{C} m^{-1}\right),\) the solution had a freezing point of \(3.66^{\circ} \mathrm{C}\). What is the molecular formula of this compound?

Draw and name all derivatives of benzene having the formula (a) \(\mathrm{C}_{8} \mathrm{H}_{10} ;\) (b) \(\mathrm{C}_{9} \mathrm{H}_{12}\).