ORGANIC CHEMISTRY AS CHEM. STUDY GUIDE

DEFINE FREE RADICALS Atoms (or groups of atoms) with unpaired electrons

DEFINE HOMOLYTIC FISSION AND DESCRIBE HOW ITS PRODUCTS ARE WRITTEN IN AN EQUATION When a covalent bond is broken to produce two free radicals Energy provided by UV light Unpaired electrons are represented by a dot

DESCRIBE HETEROLYTIC FISSION The more electronegative element in a bond takes both electrons Movement showed by a curly arrow **carbocations are positively charged ions with carbon**

ISOMERISM Structural Isomerism: chemicals with same formula behave differently because of different structures Stereoisomerism: Same atoms joined to each other in different spatial arrangements Chain: Different due to branching (moving carbon)- mostly changes boiling point Positional: Changes position of functional group Geometric (cis-trans) – double bonds only! Optical isomers (enantiomers): 4 different ends = chiral; mirror image – can’t be superimposed

DESCRIBE PHYSICAL PROPERTIES OF ALKANES. INCLUDE: GENERAL FORMULA, POLARITY, TYPE OF BONDS AND ANGLES, AND VOLATILITY PATTERNS C n H 2n+2 Nonpolar due to weak van der Waals forces Not very inert which is why it is not readily attacked in reactions. Other nonpolar reagents can react with alkanes, mostly halogens, in the presence of UV light Sigma bonds – degrees Volatility decreases as carbons increase (b.p. increases) More electrons means more energy needed to break bonds More branches lower m.p./b.p. because the straight chains can pack more tightly together whereas branches start to form a circular shape which leaves gaps

DESCRIBE PHYSICAL PROPERTIES OF ALKENES. INCLUDE: GENERAL FORMULA, TYPE OF BONDS, AND SATURATION C n H 2n Pi and sigma bonds (overlap of p orbitals) Unsaturated (presence of pi bond) Indicates it will undergo addition reactions with hydrogen and other chemicals to break double bond Oils (like vegetable oil) are made of double bonds while hard butters, etc. are saturated single bonds

WRITE THE EQUATION FOR COMPLETE AND INCOMPLETE COMBUSTION OF BUTANE

WRITE THE ENTIRE MECHANISM THE SUBSTITUTION REACTION OF METHANE AND CHLORINE (FREE RADICAL SUBSTITUTION) AND REACTION EQUATION Reaction: CH 4 (g) + Cl 2 (g)  CH 3 Cl(g) + HCl (g) 1.Initiation: homolytic fission of chlorine (in the presence of UV light) Cl—Cl (g)  Cl. (g) + Cl. (g) 2. Propagation: a chain reaction that will continue until termination step Cl. + H—CH 3 (g)  Cl—H(g) + CH 3. (g) CH 3. (g) + Cl—CL (g)  CH 3 Cl(g) + Cl. (g) 3. Termination: removes free radicals by bonding Cl. + Cl.  Cl 2 CH 3. + Cl.  CH 3 Cl CH 3. + CH.  CH 3 CH 3

WHAT TYPE OF REACTIONS DO ALKENES UNDERGO? LIST THE THREE TYPES OF THEM AND THE CONDITIONS NEEDED FOR THE REACTION Electrophilic addition Hydrogenation (addition of hydrogen to make alkane) H(g) + alkene(g)  saturated alkane Nickel catalyst, 450 K, 1000 kPa Halogenation (addition of a halogen) Will add Br, Cl, or I to each carbon at end of double bond Test for an alkene is to shake alkene with bromine water b/c it is orange but the alkene will turn it colorless CH 3 CH=CH 2 + Br 2  CH 3 CHBrCH 2 Br Hydration (addition of water) Makes alcohol 600K, 6MPa, solid catalyst of H 3 PO 4 Addition of hydrogen halide Done through acid solution (like hydrochloric acid) and halogen goes on carbon with least amount of hydrogens Reactivity increases from HF to HI (HF only reacts under pressure)

DESCRIBE MECHANISM OF ADDITION WITH ALKENES (BROMINATION) Double bond polarizes bromine Pi bond breaks and forms covalent bond with a bromine Bromine undergoes heterolytic fission (takes both electrons) while the molecule becomes a carbocation Bromide ion and carbocation rapidly form Bromine is the electrophile

DESCRIBE THE CONDITIONS AND REACTIONS OF ALEKNES WITH POTASSIUM MANGANATE(VII) Cold and dilute React readily at room temp Shaken with dilute acidified or alkaline solution Purple color disappears and diol forms CH 2 =CH 2 + H 2 O + [O]  HOCH 2 CH 2 OH ethane-1,2-diol Heated Break double bond and add double bonded oxygen to each side Aldehyde further oxidizes to carboxylic acid (make the hydrogen an –OH ) Ethene  aldehyde  methanoic acid  CO 2 and H 2 O Ketones stay ketones (no hydrogens attached)

SHOW ADDITION POLYMERIZATION REACTION OF EHTENE AND DEFINE REPEAT UNIT AND MONOMER Repeat unit: section of the polymer that is repeated to produce polymer Monomer: alkene from which polymer is made Name by saying poly(chloroethene) or whatever should go inside parenthesis