Organic Chemistry Test 2 Review Hilinski Oxidation loosing electrons loosing H Oxygen contest increases Reduction Gaining electrons gaining H Oxygen or bonds to it decrease To calculate the average oxidation you have to use what you already know O 2 H 1 N 3 in NH2 X 1 x OH Br Cl F I Addition elimination reactions taking or adding water to a molecule have no effect on the oxidation level Carbon in its most oxidized form CO2 Carbon in its most reduced form CH4 Sp3 has 0 pi bonds Sp2 has 1 pi bond Sp has 2 pi bonds Pi orbitals are parallel and they don t hold molecules together they can make bonds stronger though Single bonds are ALWAYs sigma bonds there can only be one sigma bond between atoms the rest are pi bonds Liquid nitrogen is diamagnetic repelled in a magnetic field and O2 is paramagnetic Strain and Confirmations Configuration break bonds and reform them rotations about a single bond Staggered minimum in energy Anti 180 degrees between two main groups most stable lowest in energy Gauche 60 degrees stability depends on what is interacting Eclipsed high in energy atoms are on top of each other A potential energy diagram is a graph of increasing potential energy vs torsional angel in degrees Angle strain strain a molecule has because one or more of its bond angles deviates from the ideal angle 109 5 Torsional strain destabilization that results when bonds on adjacent atoms are NOT staggered Van der Waals strain destabilization that results when atoms or groups on nonadjacent atoms are too close to one another Cyclopropane has angle strain and torsional strain because the C H bonds are all eclipsed Cyclobutane relieves this strain by adopting a puckered form The puckering decreases eclipsing interactions Cyclopentaine has small angle train but the torsional strain is substantial because of the eclipsing hydrogens in its planar form It relieves this strain by forming an envelope or half chair confirmation Cyclohexane is free of angle and torsional strain because of its chair confirmation A less stable form is the boat and less then the boat is the skew boat The boats are all above the chair still Torsional strain Methyl Primary Secondary Tertiary The most stable form of a chair will have the most strenuous alkyl group as equatorial 1 3 diaxial strain results in a less stable confirmation When drawing chairs allow axial bonds to alternate starting up from the head of the chair and down from the foot of the chair leave space in the back line of the chair for up axial bonds that come up front Stereoisomers isomers that have their atoms bonded in the same order and have the same constitution but differ in the arrangements of atoms in space usually cis vs trans Naming Spiro compounds Start numbering from smallest ring to largest Don t start numbering at the Spiro carbon Take the path that has the substituent at the lowest locant Place numbers from smallest to largest after the spiro prefix Bicyclic compounds Start counting at either bridge head and start numbering towards largest bridge giving substituents the lowest locant number It must ALWAYS have 3 number in brackets even if there is not bridge just put a 0 Anti pointing away from lowest number bridge Syn pointing towards lowest number bridge Endo pointing away from highest number bridge Exo pointing towards highest number bridge Halides go in alphabetical order and give them the lowest umber Alkyl Halides Functional class the alkyl group and halide are separate words Starts counting the chain at the carbon that has the attached halide Substitutive nomenclature use the prefix of the halogen and add it to the name of the longest carbon chain start counting on the Carbon that gives the substituted carbon the lowest number Alcohols named by placing the prefix of parent chain locant of OH group ol suffix ex hexa 7 ol For functional naming The chain is always numbered beginning with the carbon to which the OH group is attached For Substitutive naming identify the longest parent chain and replace the e ending of the alkane with ol OH groups should take precedence over alkyl groups and halogens when determining which way to number the chain I M forces from strongest to weakest Hydrogen bonding dipole dipole dispersion For hydrogen bonding the H must be bonded to a strongly electro element Dimethylether has a lower bp than ethanol As molecular weight increases so does boiling point As I M force strength increases so does bp Molecules with hydrogen bonding have higher bp then molecules with just dispersion forces The bp of chlorinated derivatives of methane increasing with the number of Cl atoms because the induced dipole induced dipole attractive forces increase with each replacement of hydrogen Because of the low polarizability of Fluorine its bp does not increase as more fluorines are added CH2 is methylene CH is Methine Perfluro each H was replaced with a Fluoride F is not very polarizable e cloud is like a gold ball I is very polarizable meaning we can deform its e cloud squishy like a nerf ball Teflon is polytetrafouraethene C2F4 PHYSICAL PROPERTIES Solubility in Water All alkyl halides are insoluble in water Anything greater then or equal to C5H12O is not soluble in water The OH group is hydrophilic lipophobic The Carbon skeleton is lipophilic hydrophobic 1 pentanol is more soluble then 1 hexanol Density RF RCl are less dense then water so they float RBr RI are denser then water so they sink ROH s are less dense then water so they float If there is more then 1 halogen then it is more dense then water Reaction Mechanisms The preparation of Alkyl Halides from Alcohols and Hydrogen Halides Sn1 The reactions will either start with an alkane or an alcohol to make the alkyl halide Alcohol Hydrogen Halide Alkyl Halide Water Order of reactivity HI HB HCl HF Primary least reactive Secondary Tertiary most reactive Tertiary alcohols are converted to alkyl chlorides VERY fast when they are mixed with HCl Secondary and Primary don t react with HC as fast so they use HBr The reaction of an alcohol with a hydrogen halide is a substitution A halogen replaces a hydroxyl group on a carbon Step 1 alkyloxonium ion Step 2 A proton from the acid breaks off and goes to the alcohol to form an A reaction is bimolecular is 2 molecules change and unimolecular is one changes The alkyloxonium ion breaks up into water and a carbocation Carbocation an ion that has a carbon with a positive charge These steps are usually unimolecular Carbocation s are usually