Petroleum Organic Chemistry

Organic Chemistry Used to be considered chemistry of living things (or things that were once living … like petroleum) Since it has been demonstrated that organic compounds can be synthesized in laboratories we now just say that Organic chemistry is the Chemistry of Hydrocarbon compounds Examples: petroleum, medicines, plastics, plants and animals …... (including YOU!!)

More than 90% of all known compounds contain Carbon (although it accounts for only 0.2% of the earth ’ s crust composition) Over 6,000,000 organic compounds have been identified – and that number is increasing daily with the synthesis of new compounds in labs

Hydrocarbons : simplest organic compounds containing only C and H atoms with “ Carbon backbones ” that are inherent to organic compounds

HOW DO YOU KNOW HOW C ’ s and H ’ s WILL GET TOGETHER TO FORM HYDROCARBONS? The Octet Rule says that everybody (except H and He) wants to have 8 outer shell electrons, Carbon has only 4 (it ’ s glass is both half empty and half full) – so instead of giving or taking electrons (Ionic bonding) it SHARES electrons – A.K.A Covalent Bonding forms Molecular compounds – (organic stuff!)

We write Lewis Dot Structures to show the sharing of electrons, and thus formation of bonds between atoms in Covalent compounds First get the number of outer shell electrons from the Group # on Periodic table Arrange electrons (dots) so that there is one dot on each of 4 sides of elements symbol, only double them up as pairs when you have more than 4 On the sides of the symbol where there is only 1 electron you will need to create a bond with another element to have a shared pair of electrons

When Carbon shares electrons to fulfill it ’ s outer shell – it needs to share with other atoms to get 4 more electrons – so it needs to make 4 bonds Hydrogen needs to make 1 bond Oxygen needs to make 2 bonds Nitrogen needs to make 3 bonds Carbon needs to make 4 bonds HONC HONC!!

A shared pair of electrons between 2 atoms is a bond, and the 2 dots representing the bond can be replaced by a line connecting the atoms – this is called a Structural formula

Can also write MOLECULAR FORMULAS that do not show the individual bonds: Expanded Molecular Formula still shows how atoms are arranged: 2, propanol = CH 3 CH(OH)CH 3 Condensed Molecular Formula just shows the number of each atom: 2, propanol = C 3 H 8 O Molecular modeling