#2: Alkanes and Cycloalkanes

Question 1

Each of the carbon atoms in an alkane has _____ and is bonded to four other atoms, each of which is either carbon or hydrogen.

Answer 1

sp3 hybrid orbitals

Question 2

One of the common methods used by organic chemists to simplify the drawings of larger molecules

Answer 2

carbon skeletal structure (also called a line- angle structure)

Question 3

the carbons of the molecule are arranged in the form of a ring.

Answer 3

cyclic hydrocarbons

Question 4

the carbon atoms that make up the ring are single-bonded to other atoms (no double or triple bonds).

Answer 4

cycloalkanes

Question 5

Cycloalkanes are composed of sp3 hybridized carbon and hydrogen atoms connected by

Answer 5

sigma bonds

Question 6

the bond angles in cycloalkanes are constrained, producing

Answer 6

ring strain

Question 7

is molecular instability resulting from carbon atoms bonded in alkanes at angles other than 109.5°.

Answer 7

angle strain

Question 8

are a combination of angle and torsional strain that determines a molecule’s stability.

Answer 8

ring strains

Question 9

Cycloalkanes, with the exception of cyclopropane, are

Answer 9

nonplanar

Question 10

Three-dimensional models of cyclopropane, such as the ______ and _____, can help to visualize ring strain caused by the eclipsed
conformation.

Answer 10

ball-and-stick model; the Newman projection

Question 11

an alkane with 11, 12, and 20 carbons

Answer 11

undecane; dodecane; eicosane

Question 12

IUPAC meaning

Answer 12

International Union of Pure and Applied Chemistry

Question 13

the base name of the compound is

Answer 13

the longest contiguous carbon chain

Question 14

For a ring with two substituents, the substituents are listed in ____.

Answer 14

alphabetical order

Question 15

When a single ring system is attached to a single chain with a greater number of carbon atoms, or when more than one single ring system is attached to a single chain, then it is appropriate to name the compounds as

Answer 15

cycloalkylalkanes

Question 16

compounds containing two fused or bridged rings.

Answer 16

Bicyclic cycloalkanes

Question 17

In bicyclic cycloalkanes, the carbon atoms common to both rings are called ____, and each bond, or each chain of atoms
connecting the bridgehead atoms is called the _____

Answer 17

bridgeheads; bridge

Question 18

branching decreases the
_____, weakens the ____, and lowers the ____.

Answer 18

surfaces area; intermolecular forces; boiling point

Question 19

Alkanes (both alkanes and cycloalkanes) are virtually _____ in water, but _____ in organic solvents.

Answer 19

insoluble; dissolve

Question 20

In most organic solvents, the primary forces of attraction between the solvent molecules are

Answer 20

Van der Waals - either dispersion forces or dipole-dipole attractions.

Question 21

2 main types of reactions that alkanes undergo

Answer 21

• combustion
• substitution reaction

Question 22

all combustion reactions are ____

Answer 22

exothermic reactions

Question 23

• a reaction where there is insufficient oxygen gas
• occurs in larger alkanes
• alkanes are not burned completely

Answer 23

incomplete combustion reaction

Question 24

is the replacement of one or more hydrogen atoms in an organic compound by a halogen (fluorine, chlorine, bromine, or iodine).

Answer 24

halogenation

Question 25

Alkanes react with halogens, such as chlorine and bromine, in the presence of

Answer 25

ultraviolet light (UV light)

Question 26

general equation of halogenation of alkanes

Answer 26

R-H + X2 (alkane + halogen2) -> R-X + HX (halocarbon + hydrogen halide)

Question 27

substance with the same molecular formula but different structures.

Answer 27

isomerism (alkanes exhibit this)

Question 28

yields alkyl halides which is an example of free radical substitution

Answer 28

halogenation

Question 29

evolves heat which is an example of oxidation

Answer 29

combustion