Chapter 3

Which of the statements below accurately describe(s) alkanes? A) Alkanes are hydrocarbons which contain only single bonds. B) Alkanes belong to the class of unsaturated hydrocarbons. C) Alkanes are the simplest and least reactive class of organic compounds. D) both A and B E) both A and C

Which of the following types of hydrocarbons is(are) saturated? A) alkanes B) alkenes C) alkynes D) aromatics E) All of the above are saturated.

If an acyclic alkane hydrocarbon contains n carbon atoms, how many hydrogen atoms must it also contain? A) n B) 2n C) n + 2 D) 2n + 2 E) n - 2

A bicyclic alkane contains 12 carbon atoms. How many hydrogen atoms does it contain? A) 20 B) 22 C) 24 D) 26 E) 28

How many methylene groups are present in 2,4-dimethylhexane? A) 0 B) 1 C) 2 D) 6 E) 8

Triacontane is an unbranched alkane that contains 30 carbon atoms in each molecule. How many hydrogen atoms are present in each molecule of triacontane? A) 30 B) 32 C) 58 D) 60 E) 62

How many secondary (2°) carbons are found in 5-ethyl-3,3,4-trimethylheptane? A) 1 B) 4 C) 2 D) 3 E) 6

How many methyl groups are present in 2,4-dimetylhexane? A) 0 B) 2 C) 4 D) 6 E) 8

When one compares the densities of n-hexane and water, one finds: A) that n-hexane is less dense than water. B) that n-hexane is more dense than water. C) that these two compounds have the same density. D) that the relative densities of two immiscible compounds cannot be measured.

A branched alkane has \_\_\_\_\_\_\_\_ boiling point relative to the isomeric linear alkane. There are \_\_\_\_\_\_\_\_ London force interactions in the branched alkane A) a higher; stronger B) a higher; weaker C) a lower, stronger D) a lower; weaker E) the same; similar

Consider the three isomeric alkanes n-hexane, 2,3-dimethylbutane, and 2-methylpentane. Which of the following correctly lists these compounds in order of increasing boiling point? A) 2,3-dimethylbutane

Place the following alkanes in order of increasing boiling point: CH3(CH2)6CH3, CH3(CH2)5CH3, (CH3)3CCH2CH2CH3

Natural gas is primarily composed of A) oxygen. B) carbon dioxide. C) methane. D) octane. E) ethanol.

Which alkanes have largely replaced Freons as propellants in aerosol cans? A) methane and ethane B) propane and butane C) pentane and hexane D) nonane and decane E) none of the above

How many carbons do the primary alkane constituents of gasoline contain? A) C1C2 B) C3C4 C) C5C8 D) C8C12 E) C12C16

________ is the reaction process through which long-chain alkanes are converted into a mixture of short-chain alkanes and alkenes.

When a mole of decane undergoes complete combustion, how many moles of water are formed? A) 1 B) 10 C) 11 D) 15.5 E) 22

The energy barrier for carbon-carbon bond rotation in propane is mainly due to \_\_\_\_\_\_\_\_. A) angle strain B) bond strain C) muscle strain D) steric strain E) torsion strain

Which of the following statements concerning the conformers of butane is true? A) Unlike ethane, all butane conformers are classified as eclipsed. B) The lowest energy conformer of butane is the gauche conformer. C) There is more torsional strain in the anti conformer than in the totally eclipsed conformer. D) The eclipsed and totally eclipsed conformers have the same amount of nonbonded strain. E) The gauche and anti conformers differ primarily in the amount of nonbonded strain present

Arrange the following conformers of butane in order of energy, lowest to highest: eclipsed, totally eclipsed, gauche, and anti.

Among the butane conformers, which occur at energy minima on a graph of potential energy versus dihedral angle? A) gauche only B) eclipsed and totally eclipsed C) gauche and anti D) eclipsed only E) anti only

Which of the following cycloalkanes exhibits the greatest molar heat of combustion? A) cyclooctane B) cycloheptane C) cyclohexane D) cyclobutane E) cyclopropane

Which of the following correctly ranks the cycloalkanes in order of increasing ring strain per methylene? A) cyclopropane

Which of the following cycloalkanes has the smallest heat of combustion per CH2 group? A) cyclopropane B) cyclobutane C) cyclopentane D) cyclohexane E) cycloheptane