Practice Problems
Problem 1
Draw a condensed structural diagram to represent each compound. Then use the IUPAC system of rules to give a correct name for the compound.
(a) 3-propanal
(b) 4-hexyne
(c) 3-propanol
(d) N-propyl-2,3-dimethylpropanamide
(e) 3-propoxypropane
Problem 2
One of the sex attractants isolated from a male boll weevil has the structure shown below.
(a) Write the molecular formula of this molecule.
(b) A student classifies this molecule as an aromatic compound. Do you agree or disagree? Give a reason for your answer.
(c) Given the shape shown for this molecule, is the molecule polar?
Problem 3
(a) Into what family of organic compounds is the compound with the molecular formula C4H9Cl grouped?
Draw and name all possible structural isomers that have the same molecular formula.
(b) Just as the alcohols are named primary, secondary, and tertiary, this family of organic compounds can be classified in a similar manner. Which isomer from (a) would be classified as tertiary? Give the reason for your answer. Problem 4
Give the IUPAC names for the compounds with the following common names.
(a) isopentane
(b) heptyl alcohol
(c) ortho-difluorobenzene
(d) amyl alcohol, C5H11OH
(e) butyric acid, C3H7COOH
Problem 5
Ethyl alcohol has a boiling point of 78.5ºC and ethylamine boils at 16.6ºC. Account for this difference in boiling point.
Problem 6
Draw a structural diagram for each of the following molecules.
(a) 1,3-dimethoxybutane
(b) N-methyl-cyclopentanamine
(c) chloropropanone
(d) 2-propylbutanoate
(e) 3-ethyl-2-pentanol
Problem 7
(a) Name the carboxylic acid and the alcohol that are used to synthesize the ester.
O
||
H3C — C(CH3)2 — CH2 — C — O — CH2 — CH3
(b) Name the carboxylic acid and the amine that are used to synthesize the amide.
O CH3
||
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H3C — C — N — CH2 — CH2 — CH3
Problem 8
(a) Give the IUPAC name and the common name for the following molecule.
CH3
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H3C — CH2 — CH2 — CH2 — CH — O — CH2 — CH2 — CH3
(b) Is this molecule polar?
(c) In a liquid sample of this substance, will hydrogen bonds exist between molecules? Explain your reasoning.
(d) Can this molecule form hydrogen bonding with isopropyl alcohol? Explain your reasoning.
Problem 9
Compare the molecules 1-butanamine, N-methyl-1-butanamine, and N,N-dimethyl-1-butanamine with respect to (a) dispersion forces between molecules, (b) polarity of molecule, and (c) solubility in water.
Problem 10
Aspartame has been used as an artificial sweetener. Identify the functional groups in the aspartame molecule shown below. Predict, giving reasons, whether or not this substance is soluble in water and in the fatty tissues in our body.
Answers
1.
(a) propanal
(b) 2-hexyne
(c) 1-propanol
(d) N-propyl-2-methylbutanamide
(e) 1-propoxypropane
2.
(a) C10H18O
(b) Disagree; since there is no benzene ring present in the molecule.
(c) The molecule does not have any symmetry, so it is polar.
3.
(a) The compound is an alkyl halide, or a haloalkane.
H3C — CH2 — CH2 — CH2 — Cl (1-chlorobutane)
H3C — CH2 — CHCl — CH3 (2-chlorobutane)
H3C — CH(CH3) — CH2 — Cl (1-chloro-2-methylpropane)
H3C — C(CH3)Cl — CH3 (2-chloro-2-methylpropane)
(b) 2-chloro-2-methylpropane would be classified tertiary because the chlorine atom
