Lesson 40 Organic Chemistry

Objectives:

- The student will explain why carbon chemistry is classified separately from inorganic chemistry.

-         The student will list the first ten straight chain alkanes.

-         The student will list the six common organic functional groups.

-         The student will classify compounds, given as names or structures, as containing one of the six common organic functional groups.

PA Science and Technology Standards: 3.4.10.A; 3.4.12.A; 3.1.10.C

I. Carbon and bonding

a. Carbon often forms bonds with four other atoms.

b. These reflect a tetrahedral type of geometry

c.      They often form long chains of atoms also

II. Carbon can form covalent networksa.  Carbon forms two common compounds, graphite and

diamondb. These two substances have properties both similar to

covalent compounds and unlike most covalent compounds.

c.      Both are considered network solids.                        i.     In diamonds, the atoms are arranged in a network

where each carbon is bonded to four other carbons.                        ii.    In graphite, the carbons are bonded to three other

carbons in layers, and then London forces hold the layers together.d.      Their properties are very different, though

                        i.      Diamonds are one of the hardest substances we know of

                       ii.     Graphite crumbles easily and is a good lubricant

III. Organic Compounds are important to life

a. All major molecules in living things, such as proteins, carbohydrates, lipids, and nucleic acids, contain carbon backbones.

b.      Organic compound – a compound containing carbon

c.      More than 6,000,000 organic compounds have been identified and named.

IV. Hydrocarbons are the simplest organic compoundsa.      Hydrocarbons are composed of only carbon and

hydrogen.b.      The simplest hydrocarbons are called alkanes, and their

names end in –ane. All of these mentioned are straight chains.

c.      The general formula for these is CnH2n+2

                                     i. methane – CH4

                                           ii.      ethane – C2H6

                                            iii.      propane – C3H8

                                            iv.      butane – C4H10

                                            v.      pentane – C5H12

                                          vi.      hexane – C6H14

                                       vii.      heptane – C7H16

                                           viii.      octane – C8H18

                                            ix.      nonane – C9H20

                                            x.      decane – C10H22

d.    You need to know these for the test!

e.      Examples – stick figure drawings:

V. Functional groups determine properties of organic molecules.

a. Most organic molecules are bonded to nitrogen or oxygen molecules, along

with the carbons and hydrogens.

b.      Functional group – group of atoms that determines an organic molecule’s

chemical properties.

c.      The compounds in each class have similar chemical properties because of the

functional groups that they possess.

d.      The name also identifies the functional group

e. Functional groups: (name, group, ending for compound names)

           i.      Alcohol – C-OH – (-ol)

 

 

 

  ii.      Ether – C-O-C – (ether)

 

 

 

  iii.      Aldehyde – CH=O – (-al)

           iv. Organic acid – COOH – (-oic acid or –ate for ionized form)

 

 

 

  v.      Ketone – C=O – (-one)

 

                                

vi.      Amine – Contains a C-N bond – (-amine, amino-, -ine, or azo-)

    vii. Ester – COO in the middle of a molecule – (-oate on the

second name)

 

 

 

 

  viii. Aromatic – Contains a benzene ring – these can be a completely

separate class of compounds, or the rings can be used as functional groups in a compound.

Structure of Benzene

f. Know these for the test!

g.   Some compounds have more than one functional group – such as amino

acids, which contain an amine (C-N) group and an organic acid (COOH) group.

h. Naming organic compounds with functional groups involves using the alkane name, and adding the

prefix/suffix for the functional group.

VI. Carbon atoms can also form ring structures

a.       Examples:

 

 

 

  

 

b. A special kind of ring structure is the benzene ring. We have seen

this above.

c.       Remember that benzene also contains several resonance structures.

VII. Organic compounds are often abbreviated

a.       In organic structural formulas, carbons and

hydrogens are not represented.

b.      This simplifies the drawing, as well as making it easier to find functional groups.

c. Example of different types of abbreviated drawings.