1. 9.4 – NOTES Petroleum and Chemical Bonding

2. A.3 Petroleum Refining
Crude oil is a mixture of many components, refining does not separate each compound
Refining produces several distinct mixtures
Fractions
Distinctive mixtures produced by large scale refining
Range of properties in each mixture
Fractions will have distinct uses

3. Fractional distillation
Process of refining crude oil
Very tall columns
Vaporized molecules continue upwards in column
The higher it gets, more molecules condense as the temperature cools
At the top, only the very lightest molecules remain a vapor
Heavy molecules stay at the bottom of the column, as temperatures cannot get high enough to boil. They are called bottoms

5. A.4 Examining Petroleum’s molecules
Intermolecular forces
Forces of attraction between molecules
Gases have very weak intermolecular forces
Weak forces allow molecules to readily separate from each other

6. Gas fractions contain compounds with low boiling points (<40C)
1-4 carbons
only slight molecular attractions
Found at the top of column

8. Liquid fractions
Boiling points between 40 and 370
Middle of column
5-20 carbons
Medium strength intermolecular forces

10. Bottoms
Boiling points greater than 370
Very greasy, do not vaporize
Strongest intermolecular forces
Chains of 21+ carbons

12. A.6 Chemical Bonding
Organic chemistry
Branch of chemistry dealing with hydrocarbons and their derivatives
Originally thought living organisms needed to produce these
Carbon chain
Backbone made of joined carbon atoms
Picture
Allows other atoms to be attached to the carbon to make them very versatile

13. Electron shells or energy levels
Electrons live in separate energy levels in the space surrounding the nucleus
Shells can only hold a certain number of electrons
Electrons must fill the inner shells before they fill the outer shells
Reactivity has to do with the number of electrons in the outer shell
Noble gases are unreactive due to having their outer shells filled with electrons; filled electron shells are stable

14. Covalent bonds
Valence electrons
Electrons in unfilled, outer shell
Only electrons that participate in bonding
Covalent bond
Sharing of 2 or more valence electrons equally to provide a filled outer shell
Three types
Can have multiple types of bonds coming off of one atom, as long as there is a total of four bonds

16. Single covalent bond
2 electrons shared between two molecules
Example C2H6

17. Double Covalent Bond
4 electrons shared
Example C2H4

18. Triple Covalent Bond
6 electrons shared
Example C2H2

19. Electron dot formulas
Lewis dot structures or Lewis structures
Show the electrons that are shared in the outer levels
1 dot = 1 electron
Carbon needs 8 electrons, H needs 2 electrons (can only make a single bond)
Structural formula
Show bonds with lines, not dots
2 electrons = 1 line
Picture:
Dot and structural formulas are 2-D representations of 3-D objects