Presentation on theme: "Introduction to Organic Chemistry and Alkanes. Organic Chemistry Molecules made up of carbon, hydrogen, and a few other elements (oxygen, nitrogen, sulfur,"— Presentation transcript:
Introduction to Organic Chemistry and Alkanes
Organic Chemistry Molecules made up of carbon, hydrogen, and a few other elements (oxygen, nitrogen, sulfur, or halogens) Amazing array of organic molecules: –Many are essential to life (phospholipids and enzymes) –Glucose and fructose –Penicillin and aspirin –Fossil fuels
Why so many Organic Compounds? I.Carbon can form stable, covalent bonds with other carbon atoms. 3 allotropes of carbon (forms of an element that have the same physical state but different properties) 1. Diamond 2. Graphite 3. Buckminsterfullerene
3 Allotropes of Carbon 1. Diamond –A large 3-dimensional network of carbon-to-carbon bonds -results in an extremely hard substance
3 Allotropes of Carbon 2. Graphite -Planar layers of carbon-to-carbon bonds that extend in 2-dimensions -Planar units slide over one another
3 Allotropes of Carbon 3. Buckminsterfullerene - “Buckey Ball” -60 Carbon atoms in the shape of a soccer ball -discovered in the 1980’s
Why so many Organic Compounds? II. Carbon can form stable bonds with other elements. -Several families of organic compounds contain oxygen atoms bonded to carbon. Others contain nitrogen, sulfur or halogens. -The presence of these elements allows for a wide variety of new chemical and physical properties on the organic compound.
Why so many Organic Compounds? III. Carbon can form double or triple bonds with other Carbon atoms. This produces a variety of organic molecules with very different properties.
Why so many Organic Compounds? IV. The structure of the compounds creates limitless possibilities. The number of ways in which carbon and other atoms can be arranged is nearly limitless. (Ex: linear chains, ring structures, and branched chains).
Isomers ISOMERS - same number and kinds of atoms but with different structures, therefore different properties “STRUCTURE determines FUNCTION”
Comparison of Organic and Inorganic Compounds PropertyOrganicInorganic BondingCovalentIonic Terms to describeMoleculeCompound Physical stateGasSolid Boiling PointLowHigh Melting PointLowHigh Solubility in waterInsolubleHigh Solubility in organic solventsHighInsoluble FlammableYesNo Conducts electricityNoYes (soln and liq)
Families of Organic Compounds Hydrocarbons Aliphatic Alkanes Contains only single bonds Alkenes Contains at least one double bond Alkynes Contains at least one triple bond Aromatic Contains benzene ring
Families of Organic Compounds Hydrocarbon – contains only hydrogens and carbon Substituted Hydrocarbon - one or more hydrogen atoms is replaced by another atom or group of atoms (functional group)
Families of Organic Compounds Aliphatic Hydrocarbon - alkanes, alkenes, & alkynes Saturated Hydrocarbon - alkanes contain only C and H have only single bonds Unsaturated Hydrocarbon – alkenes & alkynes contain only C and H have at least one carbon to carbon double or triple bond
Families of Organic Compounds Cycloalkane – carbon atoms bonded to one another to produce a ring Aromatic Hydrocarbon – contains a “benzene ring” (6 carbon atoms bonded to one another with alternating single and double bonds to form a ring)
Common Functional Groups “Structure determines Function”
Three types of formulas Molecular formula – gives the type and number of each atom present in a molecule but does not show bonding pattern – EXAMPLE: C 3 H 8 Structural formula – shows each atom and bond in a molecule –EXAMPLE: Condensed formula – shows all the atoms and places them in sequential order that indicates which atoms are bonded to which –EXAMPLE: CH 3 CH 2 CH 3 H H H H-C-C-C-H H H H
Another way to draw structures Line or skeletal structure –Only the bonds and not the atoms are shown. –A carbon atom is assumed to be at the ends and junctions of the lines –Correct number of hydrogens is mentally supplied 3-methylpentane Cl 3-chloropentane
Alkyl Groups Number of carbonsName 1Methyl 2Ethyl 3Propyl 4Butyl 5Pentyl 6Hexyl 7Heptyl 8Octyl 9Nonyl 10Decyl
Carbons are classified according to the number of other carbons to which they are attached. Primary (1°) bonded to one other carbon Secondary (2°) bonded to two other carbons Tertiary (3°) bonded to three other carbons H C-C-C-C- H C H-C-C H C C-C- C
I.U.P.A.C. Nomenclature International Union of Pure and Applied Chemistry – organization responsible for establishing and maintaining a standard, universal system for naming compounds All alkanes are the alkyl group name followed with the suffix –ane. H H H H-C-C-C-H H H H Contains 3 carbons – propyl group; Add –ane Propane
Nomenclature of Alkanes 1.Find the parent chain. A.Find the longest continuous chain of carbon atoms present in the molecule, and use the name of that chain as the parent name. CH 3 CH 2 CH 2 CHCH 3 CH 2 CH 3 CH 2 CH 3 CH 3 CHCHCH 2 CH 3 CH 2 CH 2 CH 3
Nomenclature of Alkanes 1. Find the parent chain. B. If two different chains of equal length are present, choose the one with the larger number of branches. CH 3 CH 3 CHCHCH 2 CH 2 CH 3 CH 2 CH 3
Nomenclature of Alkanes 2.Number the atoms in the main chain. A.Beginning at the end nearer the first branch point, number each carbon atom in the parent chain. CH 2 CH 3 CH 3 CHCHCH 2 CH 3 CH 2 CH 2 CH 3
Nomenclature of Alkanes 2.Number the atoms in the main chain. B. If there is branching an equal distance away from both ends of the parent chain, begin numbering at the end nearer the second branch point. CH 3 CH 2 CH 3 CH 2 CH 3 CH 3 CHCH 2 CH 2 CHCHCH 2 CH 3
Nomenclature of Alkanes 3.Identify and number the substituents. A.Assign a number to each substituent according to its point of attachment to the main chain. B. If there are two substituents on the same carbon, assign them both the same number. There must be as many numbers in the name as there are substituents.
Nomenclature of Alkanes 3. Identify and number the substituents CH 3 CH 3 CH 2 CCH 2 CH 2 CH 3 CH 2 CH 3
Nomenclature of Alkanes 4.Write the name as a single word, using hyphens to separate the different prefixes and using commas to separate numbers. A.If two or more different substituents are present, cite them in alphabetical order. B.If two or more identical substituents are present, use one of the prefixes di-, tri-, tetra-, etc but do NOT use these for alphabetizing purposes.
Name These Alkanes! CH 3 CH 3 CH 2 CCH 2 CHCH 3 CH 2 CH 3
Nomenclature for HALOGENATED ALKANES Step 1: name the parent chain CH 3 CHCH 3 Br propane Step 2: number the parent chain CH 3 CHCH 3 Br 1 2 3
Nomenclature for HALOGENATED ALKANES Step 3: name & number each ATOM or GROUP attached to the parent (the “substituent”) CH 3 CHCH 3 Br parent: propane substituent: 2-bromo
Nomenclature for HALOGENATED ALKANES Step 4: If the same substituent occurs more than once, a separate number AND a prefix (di, tri, tetra-, etc.) are used Br Br CH 3 CHCH 2 CH 2 CHCH 3 Parent: hexane Substituent: 2,5-dibromo
Nomenclature for HALOGENATED ALKANES Step 5: Place the names of the branches in alphabetical order before the parent name. Separate numbers with commas Separate names & numbers with hyphens HALOGEN substituents are placed BEFORE alkyl substituents in the name