1. What is Organic Chemistry?

2. Organic Chemistry is the study of carbon and its compounds

3. Carbon is unique among elements
Each carbon nucleus contains six protons
Each carbon atom has six electrons, but can share up to four more with other atoms
The four outer electrons are available to make four covalent chemical bonds
Carbon’s ability to share electrons with others is unmatched;
The overwhelming majority of known compounds (substances with 2 or more elements) are carbon compounds

4. Carbon Electronic Structure
Carbon’s electron configuration: 2-4 (1s22s22p2)
Halfway to a complete valence shell
Too many e- to lose, too many to gain
Carbon’s strategy: share electrons with everybody!

5. Pure Carbon
Pure carbon exists in a number of forms (allotropes)

6. Carbon is usually bonded to something else – other elements
Favorite partners: hydrogen, oxygen, nitrogen

7. Carbon can make big molecules
Carbon will form long chains with other carbon atoms
The four outer (valence) electrons are shared between the carbon and the other atoms
Because of the large number of bonds and the willingness of carbon to share electrons, there are millions of possible organic compounds

8. Structural Formulas
Because of their complexity, carbon compounds are represented in a number of ways.
CH4
Chemical Formula
3D structural formula
Structural Formula
Space-filling model

9. Carbon-Hydrogen Bonds
Carbon and hydrogen share a pair of electrons, forming non-polar covalent bonds

10. Organic Nomenclature
Millions of organic compounds need to be distinguished from one another
The IUPAC system allows us to name the most common organic compounds with some practice
We will work with sets of plastic models to build and name organic compounds

11. Representations of carbon compounds
There are numerous ways to visually describe carbon compounds
The most common are “ball and stick” models
Our models represent the shared electron pair as a grey stick
These models show the three-dimensional shapes of molecules very well
“Space filling” models are also used: they are more accurate, but less useful

12. Model Types
ball and stick space filling

13. Carbon and Hydrogen Hydrogen is carbon’s favorite partner
Hydrogen is smaller than carbon: a single proton and electron
Carbon and hydrogen share a pair of electrons equally, making a single covalent chemical bond
Compounds of carbon and hydrogen are called hydrocarbons
Liquid hydrocarbons have a very high “energy density,” and are basis for the global economy

14. Naming Hydrocarbons Hydrocarbons are the simplest organic compounds.
Hydrocarbon names have prefixes based on the longest continuous chain of carbons.
This is one of your chemistry reference tables:

15. Naming simple hydrocarbons
Straight chain hydrocarbons that contain only single bonds are called alkanes.
Alkanes have the suffix –ane on the end of a name.
Alkanes can be straight chains or carbons, or branched; we’ll start with the straight ones:

16. Name These Alkanes
What is the chemical formula for heptane?

17. Alkanes: a homologous series of hydrocarbons
All alkanes have the general formula
CnH2n+2

19. Isomers After three carbons, branched hydrocarbons become common.
Butane has two possible compounds, called isomers.
Isomers have the same chemical formula, but different structural formulas.
Butane and “iso-butane” have different physical properties.

20. Properties of Butane Isomers
Boiling point: 0.5⁰C Boiling point: -10⁰C
Iso-butane is now a common referigerant, despite the fact that it is potentially explosive.
It has replaced CFCs (chlorofluorcarbons), which destroy ozone.

21. Common names and IUPAC names
The most important organic compounds often have common names that you may have heard of…
Formaldehyde ethylene iso-butane ethylene glycol acetic acid
We will be learning the official nomenclature, called the IUPAC system.

22. Naming iso-butane methyl propane 2-
Count the longest continuous carbon chain – called the parent chain.
Be sure you have the longest chain – looks are deceiving!!
Name the parent chain using the prefixes.
Count the carbons in the parent chain and number each one.
Look for a branch. A one-carbon branch is called a methyl group.
Note the carbon number where the group is found.
methyl
propane 2-

23. Name these pentane isomers
When more than one branch is present, each one needs to be named individually, with its location on the parent as part of the name.
Another set of prefixes: di, tri, tetra, penta, etc. are used to indicate how many branches there are.

25. Condensed Structural Formulas

26. Larger hydrocarbons have lots of isomers!
The larger the hydrocarbon, the more possibility for isomers.
For example, heptane has eleven isomers:

27. Physical Properties of Hydrocarbons
Hydrocarbons are non-polar compounds.
Carbon and hydrogen share electrons more or less equally
Hydrocarbons have relatively low melting points and boiling points: the four smallest are gases at room temperature
The intermolecular attraction between molecules increases as the number of carbons increases

28. Separating Mixtures of Hydrocarbons in Crude Oil

29. Boiling Points of Alkanes
Boiling Point (°C)
Heptane
98.5
Propane
-42
Pentane 36
Butane
0.5
Methane
-161
Ethane
-88.5
Hexane ?
Be sure to unscramble these: they are not in sequence!!

30. Name the following:

31. Draw structural formulas for:
2, 3 dimethyl pentane
2-methyl hexane
3-ethyl hexane
heptane