Chemistry Unit 7: Organic Chemistry Flashcards Preview

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Flashcards in Chemistry Unit 7: Organic Chemistry Deck (18):
1

Organic compounds and carbon

Organic compound: a molecular of carbon, not including CO2, CO, and HCN
• Carbons tend to form four covalent bonds

2

Molecular and Structural formulas

Molecular:
-gives information on the types of atoms and the number of each type of atom

ex: C2H6

Structural:
-shows the bonds
-expanded version
CH3-CH3

3

Names of parent chains

1 meth-
2 eth-
3 prop-
4 but-
5 pent-
6 hex-
7 hept-
8 oct-
9 non-
10 dec-

4

Aliphatic Hydrocarbons

straight carbon chain

Includes: alkanes, alkenes, and alkynes

5

Alkanes

Single bonds →saturated hydrocarbon
CnH2n+2

Simplest alkane is methane (CH4)

Naming alkanes:
1. Find the longest chain and name it
2. Number the chain (position) with the radicals having the lowest numbers
a. Number the chains and then pick the lowest sum of the positions
b. If there is a tie, the group that comes alphabetically first gets the lowest number
3. Determine the name of the radical
a. More than one radical gets a prefix and a number for the position
4. Name (in alphabetical order of the radical ignoring the prefix and chain name last):

Position of radical A-radical A name-chain name
Or
Position of radical A-position of radical A-position of radical B-radical B name-chain name

*more than one of the same radical →di-, tri-

6

Alkenes

Double bonds →unsaturated
CnH2n
Simplest Alkene is ethene

Naming Alkenes:
1. Find the longest chain and name it
2. Number the chain (position) with the numbering beginning from the end closest to the DOUBLE bond →one less H
a. Choose the lowest number of the two
b. Put the position number for the bond before the carbon chain name
c. Next, the radical needs the lowest number
d. In general: lowest number sum of the bond and radical
3. Determine the name of the radical
4. Name (in alphabetical order of the radical and chain name last)

7

Alkynes

triple bonds →unsaturated
CnH2n-2

Simplest Alkyne is ethyne
1. Find the longest chain (carbons) and name it
2. Number the chain (position) with the numbering beginning from the end closest to the TRIPLE bond →two less H
a. Lowest number of the two is the position of the bond
3. Follow other aliphatic (straight chain) rules
a. Need lowest numbering!

8

Drawing aliphatic hydrocarbons

When drawing:
• Stick with simple linear chain with CH3 on ends and CH2 first (alkane), then change into alkenes or alkynes
• For ethyl and propyl radicals, write CH2 first, followed by CH3
• Always check!
o Longest chain
o CARBONS (4 bonds only)

9

Aromatic Hydrocarbons

derivatives of benzene (C6H6) →each vertex is a carbon with hydrogen attached
• Unsaturated
• Benzene is the simplest aromatic hydrocarbon

1) Naming: Using Benzene as the main chain
• Identify the radicals/groups attached
• With multiple groups attached: alphabetical order (automatically gets number 1)
• Still need lowest numbering (following the 1)
• Keep the methyls togethers
• Alternate naming: for two groups attached only to a benzene
o Ortho = 1, 2
o Meta = 1, 3
o Para = 1, 4
o *doesn’t have to be the same radical
• Benzene doesn’t need a position

2) Naming: Using an aliphatic hydrocarbon as the main chain
• phenyl is used to indicate benzene as a radical group (gets a position)
• must still apply aliphatic naming rules (-anes, -enes, -ynes)
• Need lowest numbering, and list radicals in alphabetical order

Drawing:
• Carbon is attached to carbon!
• Benzene→main chain
• Other →aliphatic hydrocarbon

10

Hydrocarbon Derivatives

Alcohols and organic acids

Carboxylic acids and alcohols also can have radicals

11

Alcohols

Alcohol: organic compound that contains the hydroxyl (-OH) functional group
Polar molecules (with hydrogen bonding)

• Have hydroxyl group (-OH) to a main chain
• 1) Name the longest hydrocarbon chain (CARBONS)
• 2) Number the positions (closest to OH or lowest number to OH)
• One OH group: drop the ‘e’ and add –ol
• Two OH groups: keep the ‘e’ and use –diol
• Three OH groups: keep the ‘e’ and use –triol
• The number in front of the name with the –ol gives the position of the OH group
Primary (-OH is attached to a carbon at the end of the chain), secondary (-OH is attached to a carbon that is bonded to two other carbons) and tertiary (-OH is attached to a carbon that is bonded to three other carbons) alcohols

12

Carboxylic/organic acids

Carboxylic acid:
• Compounds containing a COOH (carboxyl) group
• Always on the end
o Double bonded to a oxygen and single bonded to a hydroxyl group
• Weak acids
• Have higher melting points than hydrocarbons because of the dipole interactions of the polar carboxyl groups

Naming Carboxylic Acids:
• Drop the ‘e’ and add the suffix ‘-oic’ to the name of the parent hydrocarbon
• Name is followed by the word ‘acid’
• ***the carbon of the carboxyl group is ALWAYS #1
o therefore do not need 1 in front of name for position
Drawing Carboxylic acids:
• determine number of carbons from name (which includes the carboxylic acid group)
• ensure that each carbon has four bonds

NUMBERING CARBONS (including carboxyl groups)

13

Esters

Ester (reaction of Alcohol + Carboxylic acid = Ester) →called esterification (forming ester) or hydrolysis (splitting ester into carboxylic acid and alcohol)

Smell nice

• must write the alcohol backwards (HO)→flipping formula
• OH from acid + H from alcohol = H20
• Combine the remaining acid with remaining alcohol
• Name:
o Alcohol as a radical (-yl) first, then acid with suffix ‘oate’

14

WATCH OUT/tips

WATCH OUT:
• Taking away H for every radical (Carbons need four bonds)
• Longest chain →expanding shortform radicals
• Becoming familiar with names of alkanes
• More than one radical needs prefix/two positions
• Make sure numbering is the lowest one!
o If the bond is in the middle, choose the numbering that gives the radical the lower number! Ex: 1 bromo 2 butyne

15

Radicals

Radical groups:
Methyl CH3
Ethyl CH2 CH3
Propyl CH2 CH2 CH3
• Butyl (4 carbons), pentyl (5 carbons), hexyl (6 carbons)…

All radical groups are listed alphabetically when naming
• Halogens
o –F is Fluoro
o –Cl is Chloro
o –Br is Bromo
o –I is Iodo
Ex: 3-bromo 1-propyne
• Has three carbons
• Triple bond is between position 1 and 2
• Br radical is on position 3

Ex: 1 chloro benzene

16

Isomers of Alkanes (up to 6 carbons)

Formula CnH2n+2

Only one structure:
-C1 (CH4) methane
-C2 (C2H6) ethane
-C3 (C3H8) propane

C4 has 2 isomers:
-butane
-2-methyl propane (one radical)

C5 has 3 isomers:
-pentane
-2-methyl butane
-2, 2 dimethyl propane

C6 has 5 isomers:
-hexane
-2 methyl pentane
-3 methyl pentane
-2, 2 dimethyl butane
-2, 3 dimethyl butane

17

Isomers of Alkenes (up to 5 carbons)

CnH2n

Only one structure:
C2 (ethene)
C3 Propene

C4 has 3 isomers
-1 butene
-2 butene
-2 methyl 1 propene

C5 has 5 isomers
-1 pentene
-2 pentene
-2 methyl 1 butene
-2 methyl 2 butene
-3 methyl 1 butene

18

Isomers of Alkynes (up to 5 carbons)

CnH2n-2

Only one structure:
-C2 (1 ethyne)
-C3 (1 propyne)

C4 2 Isomers:
-1 butene
-2 butene

C5 3 isomers
-1 pentyne
-2 pentyne
-3 methyl 1 butyne