Chapter Two

Question 1

Hydrocarbon :

Answer 1

molecules with only carbons and hydrogens

Question 2

Alkanes:

Answer 2

1. type of hydrocarbon
2. does not have any functional group

Question 3

Functional group

Answer 3

Part of the molecule where
a chemical reaction occurs

Question 4

General formula for alkanes

Answer 4

CnH2n+2

Question 5

Methane

Answer 5

CH4

Question 6

Ethane

Answer 6

Ch3-Ch3

Question 7

Propane

Answer 7

Ch3-Ch2-ch3

Question 8

Butane

Answer 8

Ch3-Ch2-ch2-ch3

Question 9

what are some features of Alkane:

Answer 9

1. insoluble in water
2. good lubricants and protecting metals surface from corrosion
3. non polar
4. soluble in nonpolar or organic solvent
5. have densities lower than
   water = 0.6-0.8 g/mL
6. Boiling points of continuous Alkanes
   increase with an increase in carbon
   chain length

Question 10

what are the steps to name an organic compound:

Answer 10

Rule 1: Find the longest continuous chain of carbon atoms and use the name of this chain
as the base name of the compound
2. Rule 2: Number the longest chain, beginning with the end of the chain nearest a
substituent
3. Rule 3: Name the groups attached to the longest chain as alkyl groups. Give the location of
each alkyl group by the number of the main-chain carbon atom to which it is attached

Question 11

Constitutional isomers

Answer 11

Structural isomers
= compounds with the same molecular formula
but the carbons are connected differently

Question 12

Conformation

Answer 12

different arrangements of atoms caused by rotation of a single bond

Question 13

what are forms are conformation?

Answer 13

Staggered & Eclipsed

Question 14

T/F: Pure conformers cannot be isolated in most cases, because the molecules
are constantly rotating through all the possible conformations

Answer 14

True

Question 15

Which conformer is more stable?

Answer 15

Most stable
conformer
is staggered

Question 16

Newman projection

Answer 16

The Newman projection is the best way to judge the stability of the
different conformations of a molecule

Question 17

Butane has two different staggered conformations, explain

Answer 17

gauche (60° between the methyl
groups) and anti (180° between the methyl groups)

Question 18

T/F:The eclipsed conformation where the dihedral angle between the methyl groups is 0° is
referred to as totally eclipsed

Answer 18

True

Question 19

Newman Projection: steps

Answer 19

1) Determine which bond is being considered
2) Determine which atom is front atom of bond being considered
3) The substituents attached to the front atom are drawn to a point,
the substituents attached to the back atom are drawn to a circle
4) The relative angles and orientation of the substituents are
maintained

Question 20

Cycloalkane

Answer 20

Cyclic Hydrocarbon without functional group, general formula: CnH2n

Question 21

what are the factors that affect stability in cycloalkanes?

Answer 21

Angle strain, & Torsional strain

Question 21

what are the features of cycloalkanes:

Answer 21

Nonpolar
-Not soluble in water
-Density similar to alkanes
-Boiling point depends in
ring size

Question 21

Angel Strain

Answer 21

from the compressing of the bond angles

Question 21

Torsional strain

Answer 21

from eclipsing of the bonds

Question 22

The most stable conformation of cyclohexane is
the chair form shown to the right. The C-C-C bonds are
very close to 109.5o, so it is almost free of angle strain.
It is also a fully staggered conformation and so is free of
torsional strain

Answer 22

True

Question 23

Stereoisomers

Answer 23

Same connectivity (not constitutional isomers),
but differing arrangement in space

Question 24

stereoisomers are :

Answer 24

1. Cis: same side
2. Trans: Opposite side