Chapter 11- Introduction to Organic Chemistry

Question 1

What is an empirical formula?

Answer 1

Formula showing simplest integer ratio of atoms of each element in a compound.

Question 2

What is a molecular formula?

Answer 2

Formula showing actual number of atoms of each element in a compound.

Question 3

What formulae other than molecular formulae and empirical formulae are there?

Answer 3

Structural, displayed, skeletal

Question 4

What are the first six roots in IUPAC naming?

Answer 4

meth-
eth-
prop-
but-
pent-
hex-

Question 5

What is the functional group and suffix for alkenes?

Answer 5

C=C double bond
-ene

Question 6

What is the functional group and suffix for alkanes?

Answer 6

C-C bonds (no double bonds)
-ane

Question 7

What is the functional group and suffix for ketones?

Answer 7

C=O
-one

Question 8

What is the functional group and suffix for alcohols?

Answer 8

-OH
-ol

Question 9

What is the functional group and suffix for aldehydes?

Answer 9

-COH
-al

Question 10

What is the functional group and suffix for carboxylic acids?

Answer 10

-COOH
-oic acid

Question 11

What is the functional group and PREfix for haloalkanes?

Answer 11

R-X (X = F, Cl, Br, I)
fluoro-
chloro-
bromo-
iodo-

Question 12

How is the position of a side chain or functional group shown?

Answer 12

A number (locant) is used to give its position along the chain.
Carbon atoms in the chain are numbered (so that name has lowest total) and the number goes before the functional group, eg 2- bromo-.
For C=C bond, the number of the atom which it COMES from is given.

Question 13

How is the number of side chains or functional groups shown?

Answer 13

Prefix included showing the number:
di- 2
tri- 3
tetra- 4

Question 14

How are the side chains and functional groups ordered in the name?

Answer 14

Alphabetically, ignoring prefixes like di, tri, tetra.

Question 15

What are side chains of different lengths called?

Answer 15

1: methyl-
2: ethyl-
3: propyl-
4: butyl-

Question 16

What is a homologous series?

Answer 16

A family of organic compounds with the same functional group but different carbon chain length.

Question 17

How does carbon chain length of a homologous series affect properties?

Answer 17

Physical: Melting, boiling point increases as number (and strength) of VdW forces increases. -Volatility, flammability decreases, viscosity increases
Has little effect on the chemical reactivity of the functional group.

Question 18

How does chain branching affect melting point?

Answer 18

Reduces melting point as the molecules pack together less well.

Question 19

What does a curly arrow show?

Answer 19

The movement of electrons. Double headed arrow shows a pair, single headed shows one.
Moves from a covalent bond or lone pair of electrons to a positively charged area.

Question 20

What are structural isomers?

Answer 20

Molecules with the same molecular formula but different structural formulae.

Question 21

What are the three types of structural isomer?

Answer 21

Chain, positional and functional group isomers

Question 22

What are positional isomers?

Answer 22

Molecules with the same functional group but in different positions,
eg but-1-ene and but-2-ene

Question 23

What are functional group isomers?

Answer 23

Molecules with the same molecular formula but different functional groups,
eg C5H10 as pent-1-ene or cyclopentane

Question 24

What are chain isomers?

Answer 24

Molecules with the same molecular formula but different carbon chain lengths,
eg butan-1-ol and 2-methylpropan-1-ol

Question 25

What are stereoisomers?

Answer 25

Molecules with the same structural formula but different arrangements of bonds in space, eg optical and E-Z isomers

Question 26

What are E-Z isomers?

Answer 26

Molecules in which the substituents either side of a C=C bond are the same but in different positions. They can be the same side (Z) or opposite sides (E).

Question 27

Why are there E-Z isomers?

Answer 27

There is restricted rotation about a planar carbon-carbon double bond so the E and Z isomers are separate compounds.

Question 28

What are the Cahn-Ingold-Prelog (CIP) priority rules used for and what are they?

Answer 28

To determine whether an isomer is E or Z, we must know the priority group on each side of the bond. The CIP rules say that the substituent on each side with the highest mass is the priority group. If the atoms have the same mass, go along the chain until it differs.

Question 29

What is a free radical?

Answer 29

A species with an unpaired electron. They are extremely reactive. (When a covalent bond splits homolytically, one electron goes to each atom that was originally bonded so they now each have an unpaired electron)

Question 30

What are the three stages in a free-radical substitution?

Answer 30

Initiation, propagation, termination

Question 31

What is the initiation step in free radical substitution?

Answer 31

Cl-Cl bond broken under exposure to UV light. Bond broken homolytically so one electron goes to each Cl atom, forming 2 chlorine free radicals

Question 32

What is a necessary condition to start the free radical substitution chain reaction?

Answer 32

UV light which breaks the Cl-Cl bond

Question 33

What are the two steps in the propagation step?

Answer 33

Free radical takes H atom from CH4 forming HCl and making CH4 now a free radical: .CH3 .CH3 then reacts with Cl2 to form CH3Cl leaving a free radical (chain reaction, free radical formed again)

Question 34

What is the termination step?

Answer 34

End step in which free radicals are removed Any two free radicals react to form a stable compound, eg 2Cl. --> Cl2