Organic - pertaining tolife Living or was onceliving Organic Chemistry -The chemistry of carboncompounds Carbon is wellsuited for life because it isthe most versatile elementin terms of bonding.
Carbon (C) appears in the 2nd row of the.periodic table and has atomic number of 6. Givenour discussion of electron shells it is easy to seethat carbon has 4 electrons in its valence shell.Since carbon needs 8 electrons to fill its valenceshell, it forms 4 bonds with other atoms (eachbond consisting of one of carbons electrons andone of the bonding atoms). Every valenceelectron participates in bonding, thus a carbon atoms bonds will bedistributed evenly over the atoms surface. Thesebonds form a tetrahedron, as illustrated below :
Carbon can form four bonds.They can be single, double or triplebonds.Carbon will not form diatomicmolecules like other small atomsdo.It can form long carbon chainscontaining strong, short, covalentbonds.
Allotropes forms of the same elementthat differ in their bonding There areseveral allotropes of carbonDiamond – tetrahedral network ofcarbon atoms (every atom is lockedinto place (hardness)Graphite – sheets can slide over eachother (lubricant)
Amorphous carbon charcoal, soot,coke Amorphous has not setarrangement of atoms. It has irregularpatterns of high surface area, deep“caves” that can trap other moleculesFullerenes – spherical molecules (60atoms) see page 807, mostlyexperimental at this point.
Hydrocarbons.molecules that containonly hydrogen andcarbon
Fossil FuelsNatural gas - mostly methaneCrude oil - mixture of hydrocarbon chainsfrom propane to butane, octane andlonger Components separated usingfractional distillation (see page 823)Coal - mostly impure carbon (coke - purecarbon from coal, charcoal - pure carbonfrom wood)
Types of Formulas(examples) Compound – hexane .Empirical formula. Molecular formula .Structural formula.Condensed structuralformula
CLASSIFICATION OF ORGANIC COMPOUNDS ALKANES - Compounds that containonly hydrogen and single bondedcarbons. (carbon chains surroundedby hydrogens). Named with an ane ending that ispreceded with a prefix which giveshow many carbons that are in thecarbon chain.
An organic molecule (hydrocarbon) isformed when carbon bonds tohydrogen. The simplest hydrocarbonconsists of 4 hydrogen atoms bondedto a carbon atom (called methane):Methane
In addition to binding to hydrogen, carbon canalso bind to other carbon atoms, as illustratedbelow:In fact the uniqueness of carbon comes from thefact that it can bind to itself. Carbon atoms canform long chains:branched chains: Ethane Hexane
Carbons can formin ring shapesCyclohexane
Saturated vs Unsaturated HydrocarbonsSaturated carbons are single bonded andhave a greater compliment of hydrogen.( hence, saturated )Unsaturated carbons are generally doubledbonded and thus are attached to fewerhydrogen.
In fact, there appears to be almost no limit to the number of different structures thatcarbon can form. To add to the complexity of organic chemistry, neighboring carbonatoms can form double and triple bonds in addition to single carbon-carbon bonds:Single, double, and triple bonds :Keep in mind that each carbon atom forms 4 bonds. As you increase the number ofbonds between carbon atoms, the number of hydrogen atoms in the moleculedecreases.
. Nomenclature (naming compounds): The simplest hydrocarbons are those that contain onlycarbon and hydrogen. As we have seen, these come inthree varieties: 1) alkanes, molecules with only singlebonds, 2) alkenes, those with one or more double bondand 3) alkynes, those with one or more triple bond.Basic organic chemistry can be thought of as a molecularErector Set, if you know the number of carbon atomsand the type of bonds in a molecule, you can build themolecular structure
To describe the number of carbon atoms in a hydrocarbon, chemists use prefixes in themolecules name. The first 10 prefixes used in organic chemistry are shown below. Tocomplete the hydrocarbon name, the prefix is attached to the ending of the root word(drop the alk- from the words alkane, alkene or alkyne) to describe the type of bondingon the molecule. Hydrocarbon prefix # of C atoms name formula structureMeth 1 methane CH4 Eth 2 ethane C2H6 Prop 3 propane C3H6
Hydrocarbon prefix # of C atoms name formula structurebut 4 butane C4H10pent 5 pentane C5H12hex 6 hexane C6H14hept 7 heptane C7H16oct 8 octane C8H18non 9 nonane C9H20dec 10 decane C10H22
14. Alkanes (Single Bonds)As we have discussed, each carbon atom has 4 bonds.As you add carbon to a molecule, the empty carbonbonds are filled with hydrogen atoms (or other elements,as we will soon see). You can calculate the number of Hatoms in the simple alkanes. The number of H atoms ina simple alkane equals two times the number of carbonatoms plus 2, or (2n + 2), where n is the number ofcarbon atoms in the molecule.
Alkenes (double bonds) The simple alkenes have 1 double bond and 2fewer H atoms in the molecule; the number of Hatoms in the simple alkenes = (2n). Simplealkynes contain 1 triple bond 2 fewer H atomsthan the alkene, or (2n - 2) H atoms.
Functional Groups In addition to carbon andhydrogen, hydrocarbons can also containother elements. The alcohols, for example,are a group of hydrocarbons in which ahydroxol (-OH) group is bound to a carbonskeleton.
These compounds are named like the simplehydrocarbons, a prefix attached to a root ending (-anolfor the alcohols). Thus ethanol, is a 2 carbon alcohol withthe structure: Most people are familiar with this organic compound asit is the active ingredient in "alcoholic" beverages such asbeer and wine.
. While the simple hydrocarbons are important, they do not themselves commonly occurin living organisms (except for during the occasional bout of methane flatulence).
. The simple hydrocarbons are the building blocks of more complex molecules thatmake up living organisms. In the next few weeks, I will introduce some of thesemolecules and their biochemistry, the chemistry of life. Alcohol (Hydroxyl Group)Aldehyde (Carbonyl Group) Ketone (Carbonyl Group) Carboxylic Acid (CarboxylGroup) Amine (Amino Group) Amino Acid (Amino Group + Carboxyl Group)
Great site that helps to match the funtional group to it’s structure.http://biology.clc.uc.edu/courses/bio104/carbon.htm Many important organicchemistry molecules contain oxygen or nitrogen. Its a good idea to memorize the namesand structures of these functional groups.
. ALKANES SUBSTITUDED WITHHALOGENS Give the position of thehalogen (F, Cl, Br, or I) and then give thename of the halogen with an "o" ending. 3-chloro-2-methylpentanebromochloroiodomethane
.Conformational isomers - molecules with thesame structure but with different bond rotation.Molecules with single bonds can rotate about thesingle bond. These are the same compound. Theyhave the same melting point, the same boilingpoints and the same chemistry. The higher thetemperature the faster they change back andforth from one form to the other. Example:cyclohexane (chair and boat conformation)
Structural isomers - molecules that have thesame molecular formula but have differentstructural formulas. These are differentcompounds with different melting pointsand different chemistry Examples C5H12(pentane, 1 methyl butane, 2,2 dimethylpropane)
SUBSTITUTED ALKANES Fisher Projection - away to show the 3-dementional character of amolecule. Examples: CHFClI A carbon that has 4different groups bonded to it is called a chiralcarbon. Enantiomers - (mirror image isomers) -two arrangements around a chiral carbon thatcannot be rotated in such a way as to besuperimposed on each other.
They are different molecules that have thesame formula, same boiling points andmuch of the same chemistry. Theirchemistry differs when they are reactingwith molecules that also have chiralcarbons. (biological systems) They alsorotate polarized light in opposite directions.Vitamin C is an example of this type ofmolecule
. UNSATURATED HYDROCARBONS Ifthe molecule is filled to capacity withhydrogen the compound is saturated(alkanes). If the molecule is cyclic, containsa double bond or contains a triple bond it isunsaturated. Saturated fats are fromanimals and are not good for you.Unsaturated fats are from plants