Chem 101 1st Edition Lecture 3 Outline of Last Lecture I Organic Chemistry A Definition B Elements II Organic Molecules A Properties B Polar Bonds C Multiple Bonds D Fatty Acids III Functional Groups IV Line Structures Outline of Current Lecture I Representing Organic Molecules II Conformations of Organic Molecules III Hydrocarbon Functional Groups IV Naming Organic Molecules Current Lecture I II Representing Organic Molecules A Expanded Structure shows all bonds B Condensed Structure a shorthand way of drawing structures in which C C and CH bonds are understood rather than shown not line structures 1 A chain of CH2 can be shown in parentheses with a subscript indicating how many there are For example CH2CH2CH2 can be shown as CH2 3 Conformations of Organic Molecules A Groups around a C C single bond will rotate around the bond in a 109 5 degree angle B Groups around a C C bond are flat with a 120 degree angle C Conformation the specific 3D arrangement of atoms in a molecule achieved specifically thru rotations D Conformers molecular structures having identical connections between atoms and represent identical molecules 1 To determine if two structures are conformers or isomers identify if their IUPAC names are the same These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III IV E Isomers molecular structures with the same molecular formula but not the same structure different molecules 1 Two isomers are possible when groups are attached to a double bond but will not form if a carbon atom is attached to identical groups a Cis groups are attached on the same side of the double bond b Trans groups are attached on opposite sides c The prefix cis and trans are placed in front of an alkene name when there are cis and trans isomers Hydrocarbon Functional Groups organic compounds that only contain carbon and hydrogen atoms A Alkanes only single bonds 1 Cycloalkanes ring structured alkanes with 2H fewer than their corresponding alkane B Alkenes contains at least one double bond C Alkyne contains at least one triple bond D Aromatic a six membered ring of carbons containing three alternating double bonds resonance E Saturated a molecule whose carbon atoms bond to the maximum number of hydrogen atoms F Unsaturated a molecule with a carbon carbon multiple bond having fewer hydrogen atoms than a single bond Naming Organic Molecules International Union of Pure and Applied Chemistry A The names of organic molecules can be determined using the IUPAC system B The IUPAC system includes a prefix to determine how many carbon atoms are present an ending to denote the functional group and prefixes to name other groups C Alkanes have the ending ane D Alkenes have the ending ene E Alkynes have the ending yne F Steps for writing an IUPAC names 1 Identify the longest carbon chain 2 Number the chain from the end nearest the substituent functional group unless there s a multiple bond then number from the end nearest the multiple bond 3 Give the location of the substituent and the multiple bond