Today’s Lecture 10.1 Learning Objectives 10.2 Unique of Carbon 10.3 Isomer 10.4 Functional Group 10.5 Saturated vs Unsaturated 10.6 IUPAC Naming Topics Covered
“ Organic chemistry is enough to drive one mad. It gives the impression of a primeval tropical forest of the most remarkable things, a monstrous and boundless thicket with no way of escape, into which one may well dread to enter” Frederich W ö hler (1835)
Learning Objectives: 1) Identify the multiple bonding character of carbon atoms 2) Identify carbon as the "backbone" of organic chemistry 3) Define hydrocarbon, alkane, alkene, alkyne, cyclic, and aromatic as they relate to organic compounds 4) Classify a hydrocarbon as either saturated or unsaturated compare the geometry of single, double, and triple bonds between two carbon atoms
5) Compare the rotational ability in single, double, and triple bonds name and draw structures of alkanes, alkenes, and alkynes up to C10
6) Recognize and name the substituent groups methyl, ethyl, fluoro, chloro, bromo, and iodo name and draw structures of simple
substituted alkanes to C10
7) Describe the term functional group and relate it to classes of compounds
8) Identify a compound as an alcohol, aldehyde, ketone,ether, organic acid, ester, amine, or amide when given a structural diagram
The Study of Carbon Compounds
(some exceptions: for example carbonates, carbon dioxide, etc.)
Example of organics chemical:
Food – carbohydrates, fats, protein
Clothing – silk, linen, wool, cotton etc.
Detergents and soap
Organic vs Inorganic: Differences Organic Inorganic Bonding Covalent Ionic Physical State (room temp) Gas/liquid common Solids common Melting points Tend to be low Tend to be very high Soluble In water Tend to be insoluble Much higher percent soluble Conductivity Nonconductors Conduct in solution and molten
Why Is Carbon Unique?
1. Forms four covalent bonds
2. Bonds covalently to: H, O, N, P, S, and all other nonmetals (except noble gases)
3. Carbon atoms join to form:
Chains and Rings
4. Carbon can form multiple bonds to itself, oxygen, and nitrogen. Example:
Homologous series: series of compounds with similar chemical properties, each member differs from the previous one by the addition of a –CH2- group. The general characteristics of a homologous series are: 1) same functional group and similar chemical properties. 2) differs from the next in the series by a –CH2- group. 3) may be prepared by similar methods. 4) The physical properties- show a progressive change with increasing relative molecular mass. 5) contain the same elements and can be represented by the same general formula. General Formulae
General Formulae Homologous series General formula Alkanes C n H 2n+2 Cycloalkanes C n H 2n Alkenes C n H 2n Cycloalkenes C n H 2n-2 Alkynes C n H 2n-2 Haloalkanes C n H 2n+1 X (X= Cl, Br, I) Alcohols C n H 2n+1 OH C n H 2n+2 O
General Formulae Homologous series General formula Aldehyde C n H 2n O Ketones C n H 2n O Carboxylic acids C n H 2n O 2 C n H 2n+1 COOH Esters C n H 2n O 2 Amine C n H 2n+1 NH 2 Amide C n H 2n+1 CONH 2
The general formula for an organic compound can also be written by using the symbol R to represent the alkyl group, C n H 2n+1 or the phenyl group, C 6 H 5 .
(R’ and R’’ represent two alkyl groups. The alkyl groups can be the same or different.)
The phenyl group (- C 6 H 5 ) has the structural formula of:
General Formulae Homologous series General formula Alkanes RH Aldehydes RCHO Ketones R’COR’’ Alcohols ROH Carboxylic acids RCOOH Esters R’COOR’’ Amines RNH 2 Amides RCONH 2
The IUPAC (International Union of Pure and Applied Chemistry) is responsible for chemistry names.
In the IUPAC system, the chemical name of an organic compounds has three parts:
prefix, parent and suffix
1) The prefix of the chemical name gives information about the substituent present,
2) the parent gives the number of carbon atoms present in the molecule
3) the suffix gives the name of the homologous series.
Systematic Naming Example: IUPAC name for BrCH 2 CH 2 COOH is Prefix: bromo Parent: propan Suffix: oic 3–bromopropanoic acid
Saturated compounds (alkanes) have the maximum number of hydrogen atoms attached to each carbon atom Unsaturated compounds have fewer hydrogen atoms attached to the carbon chain than alkanes Unsaturated compounds contain double or triple bonds Saturated and Unsaturated Compounds
Molecules contain one or more carbon-carbon double (C=C) or triple (C≡C) bonds
There are three classes of unsaturated
1. alkenes and cycloalkenes, CnH2n
2. alkynes and cycloalkynes, CnH2n-2
3. aromatic hydrocarbons
Alkanes, C n H 2n+2
Contain C and H only
Contain single bonds C-C
Have 4 bonds to every carbon (C) atom
Alkanes, C n H 2n+2
The bonding around each carbon atom is tetrahedral, so all bond angles are 109.5°.
As a result, the carbon atoms in higher alkanes are arranged in zig-zag rather than linear patterns.
General Formulae IUPAC Name # Carbon Molecular formula Structural formula /Condensed formula Meth ane 1 CH 4 CH 4 Eth ane 2 C 2 H 6 CH 3 CH 3 Prop ane 3 C 3 H 8 CH 3 CH 2 CH 3 But ane 4 C 4 H 10 CH 3 CH 2 CH 2 CH 3 Pent ane 5 C 5 H 12 CH 3 CH 2 CH 2 CH 2 CH 3 Hex ane 6 C 6 H 14 CH 3 CH 2 CH 2 CH 2 CH 2 CH 3 Hept ane 7 C 7 H 16 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Oct ane 8 C 8 H 18 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Non ane 9 C 9 H 20 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 Dec ane 10 C 10 H 22 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3
Alkane- IUPAC Names
Before learning the IUPAC rules for naming alkanes, the names and structures of eight alkyl groups must be learned.
These alkyl groups are historical names accepted by the IUPAC and integrated into modern nomenclature.
An alkyl group is an alkane with one hydrogen atom removed. It is named by replacing the ane of the alkane name with - yl .
Methane becomes a methyl group.
All six hydrogens on ethane are equivalent. Removing one H generates the ethyl group.
Synthetic polymers provide a wide variety of items that we use every day.