ORGANIC CHEMISTRY BASICS
OVERVIEW
q Organic Chemistry Used to be considered chemistry of living things (or things that were once living… like petroleum)
q Since it has been demonstrated that organic compounds can be synthesized in laboratories we now just say that Organic chemistry is the Chemistry of Carbon compounds
o Examples: petroleum, medicines, plastics, plants and animals…... (including YOU!!)
q More than 90% of all known compounds contain Carbon (although it accounts for only 0.2% of the earth’s crust composition)
q Over 6,000,000 organic compounds have been identified – and that number is increasing daily with the synthesis of new compounds in labs
q
Some Examples:
What is the Deal with petroleum and how does it fit into the organic chemisty scheme?
q PETROLEUM … Black Gold … Texas Tea
o Petroleum is a Non-renewable organic resource
o Consists of a mixture of hydrocarbons of many different carbon chain lengths
o Hydrocarbons : simplest organic compounds containing only C and H atoms with “Carbon backbones” that are inherent to organic compounds
Some examples:
o Carbon bonds contain potential energy (actually all bonds contain energy) – the beauty of petroleum is that the long chains of carbons connected to one another contain a lot of bonds – and therefore a lot of potential energy
o Petroleum is used for:
q Gasoline
q Heat / electricity
q Raw materials for:
o Plastics: Polyethylene, Vinyl, Polypropylene…
o Pharmaceuticals: Lipitor, Prozac, Coumadin…
o Synthetic fibers: Nylon, Rayon, Teflon, Kevlar…
q A quote from our nutty Russian friend Mendeleev regarding using petroleum as an energy source: he said it would “be akin to firing up a kitchen stove with a bank note”
HOW DO WE GET ALL OF THESE DIFFERENT PRODUCTS FROM THAT THICK BLACK SLUDGE?
o Petroleum removed from the ground as “Crude Oil” is sent to the Refinery for processing – separating by distillation into fractions of similar carbon chain lengths
WHAT ARE THE POLITICAL RAMIFICATIONS OF BEING A SOCIETY THAT IS SO DEPENDENT ON PETROLEUM AS AN ENERGY SOURCE?
q 60% of all the petroleum in the world is in 5 countries: Iran, Iraq, Kuwait, Saudi Aradia, and UAE
q The U.S. petroleum reserves from Prudhoe Bay in Alaska would be enough to supply our energy needs for less than 2 years
q Petroleum cost is determined by supply/ demand (or projected supply/demand) i.e. What happened the day after 9/11 at the gas pumps?
q The search for alternative fuels in the 80’s ceased due to cheap crude oil prices (70-90 cent/gallon gas prices)… we got lazy
q Gee Dubya just proposed a 2000$ tax write off for anyone who owns a hybrid gas – electric car (the irony here is that the electricity that is the alternative fuel for the car is most probably obtained from burning petroleum at the power plant!)
HOW DO YOU KNOW HOW C’s and H’s WILL GET TOGETHER TO FORM HYDROCARBONS?
q 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
q COVALENT BONDING forms Molecular compounds – (organic stuff!)
q 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
o Carbon needs to make 4 bonds
o Oxygen needs to make 2 bonds
o Hydrogen needs to make 1 bond
o Nitrogen needs to make 3 bonds
q We write Lewis Dot Structures to show the sharing of electrons, and thus formation of bonds between atoms in Covalent compounds
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Example of Lewis Dot structure for C and for H
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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
q Can also write MOLECULAR FORMULAS that do not show the individual bonds
o Expanded Molecular Formula still shows how atoms are arranged:
· 2, propanol = CH3CH(OH)CH3
o Condensed Molecular Formula just shows the number of each atom:
· 2, propanol = C3H8O
Classes of ORGANIC COMPOUNDS
o Alkanes – simplest hydrocarbons – just C and H, and all single bonded – no funny business!!
·
Propane =
o Alkenes – just like alkanes, but they have at least 1 carbon – carbon double bond
·
Propene =
o ALKYNES – you know what they say… “it takes all kines” tee hee – just like alkanes, but they have at least 1 Carbon – Carbon triple bond
·
Propyne =
q Carbon chain lengths effect physical properties of the compounds – check out how the intermolecular forces between carbon compounds with increasing numbers of carbons effects the boiling points of these compounds – Your turn pg. 175)
q You Decide pg. 173 – uses of fractions