prelim org chem lesson 1

Question 1

a compound composed of only carbon and hydrogen.

Answer 1

hydrocarbon

Question 2

only carbon single bonds

Answer 2

alkanes

Question 3

one or more carbon carbon;double bonds

Answer 3

alkenes

Question 4

one or more carbon;triple bonds

Answer 4

alkynes

Question 5

one or more benzene like rings

Answer 5

benzene

Question 6

A line represents a carbon-carbon bond and a vertex and a line terminus represent a carbon atom.

Answer 6

line-angle formula

Question 7

are not shown in line-angle formulas.

Answer 7

Hydrogen atoms

Question 8

compounds that have the same molecular formula but different structural formulas (different connectivity).

Answer 8

Constitutional isomers:

Question 9

only one structural formula is possible; there are no constitutional isomers for these molecular formulas.

Answer 9

the molecular formulas CH4, C2H6, and C3H8

Question 10

two constitutional isomers are possible.

Answer 10

the molecular formula C4H10

Question 11

the number of carbon atoms in the chain.

Answer 11

a prefix

Question 12

shows that the compound is a saturated hydrocarbon.

Answer 12

the suffix -ane:

Question 13

the longest chain of carbon atoms

Answer 13

a parent name`

Question 14

the groups bonded to the parent chain

Answer 14

substituent names

Question 15

a substituent group derived from an alkane by removal of a hydrogen atom.

Answer 15

Alkyl group

Question 16

commonly represented by the symbol R-.

Answer 16

Alkyl group

Question 17

named by dropping the -ane from the name of the parent alkane and adding the suffix -yl.

Answer 17

Alkyl group

Question 18

consists of a prefix showing the number of carbon atoms and the ending -ane.

Answer 18

alkane

Question 19

rules to remember in IUPAC NAME

Answer 19

Do not include the prefixes di-, tri-, tetra-, and so on, or the hyphenated prefixes sec- and tert- in alphabetizing;
alphabetize the names of substituents first, and then insert these prefixes

If there is one substituent, number the parent chain from the end that gives the substituent the lower number.

If the same substituent occurs more than once:
Number the parent chain from the end that gives the lower number to the substituent encountered first.
Indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so on.
Use a comma to separate position numbers.

Question 20

The first three alkanes

Answer 20

methane, ethane, and propane.

Question 21

shows that one end of an otherwise unbranched chain terminates

Answer 21

iso

Question 22

a hydrocarbon that contains carbon atoms joined to form a ring.

Answer 22

Cyclic hydrocarbon

Question 23

a cyclic hydrocarbon in which all carbons of the ring are saturated.

Answer 23

Cycloalkane

Question 24

ring sizes ranging from 3 to over 30 carbon atoms are found in nature.

Answer 24

Cycloalkanes

Question 25

are especially abundant in nature.

Answer 25

Five-membered (cyclopentane) and six-membered (cyclohexane) rings

Question 26

rules to remember for cycloalkanes

Answer 26

If there is only one substituent on the ring, there is no need to give it a location number. If there are two substituents, number the ring beginning with the substituent of lower alphabetical order.

Question 27

three-dimensional arrangement of atoms in a molecule that results by rotation about a single bond.

Answer 27

Conformation

Question 28

The most stable conformation of a cyclopentane ring is an

Answer 28

envelope conformation

Question 29

The most stable conformation of a cyclohexane ring is the

Answer 29

chair conformationn

Question 30

all bond angles are approximately

Answer 30

109.5°

Question 31

six C-H bonds are

Answer 31

equatorial and axial

Question 32

on the same side

Answer 32

cis

Question 33

across from

Answer 33

trans

Question 34

Because cis-trans isomers differ in the orientation of their atoms in space, they are

Answer 34

stereoisomers

Question 35

In Ch 15, we study another type called

Answer 35

enantiomers

Question 35

Cis-trans isomers are one type of

Answer 35

stereoisomer

Question 36

The electronegativity difference between carbon and hydrogen is 2.5 - 2.1 =

Answer 36

0.4 on the Pauling scale

Question 37

are nonpolar compounds and the only interaction between their molecules are the very weak London dispersion forces.

Answer 37

alkanes

Question 37

lower than those of almost any other type of compound of the same molecular weight.

Answer 37

Boiling points of alkanes

Question 38

are not soluble in water; they are unable to form hydrogen bonds with water.

Answer 38

Alkanes

Question 39

are soluble in each other.

Answer 39

Alkanes

Question 40

are also soluble in other nonpolar organic compounds, such as toluene and diethyl ether.

Answer 40

Alkanes

Question 41

is the basis for their use as energy sources for heat [natural gas, liquefied petroleum gas (LPG), and fuel oil] and power (gasoline, diesel fuel, and aviation fuel).

Answer 41

oxidation

Question 42

Halogenation of an alkane is

Answer 42

Halogenation of an alkane

Question 43

manufactured under the trade name Freon

Answer 43

Chlorofluorocarbons (CFCs)

Question 44

are nontoxic, nonflammable, odorless, and noncorrosive.

Answer 44

Chlorofluorocarbons (CFCs)

Question 45

CFCs were used as;

Answer 45

heat-transfer agents in refrigeration systems. industrial cleaning solvents to prepare surfaces for coatings and to remove cutting oils from millings. propellants for aerosol sprays.

Question 46

cause destruction of the Earth’s stratospheric ozone layer.

Answer 46

Chlorofluorocarbons or CFCs

Question 47

The most prominent replacements are the

Answer 47

hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs)

Question 48

These compounds are chemically more reactive than CFCs and are destroyed before they reach the stratosphere.

Answer 48

hydrochlorofluorocarbons (HCFCs)

Question 49

90 to 95 percent methane

Answer 49

Natural gas

Question 50

5 to 10 percent ethane

Answer 50

Natural gas

Question 51

a mixture of other relatively low-boiling alkanes, chiefly propane, butane, and 2-methylpropane.

Answer 51

Natural gas

Question 52

A thick, viscous liquid mixture of thousands of compounds, most of them hydrocarbons formed from the decomposition of marine plants and animals.

Answer 52

Petroleum

Question 53

1 carbon= 2carbon= 3carbon= 4carbon= 5carbon= 6carbon= 7carbon= 8carbon= 9carbon= 10carbon=

Answer 53

methane ethane propane butane pentane hexane heptane octane nonane decane