Organic Molecules

alkanes

saturated hydrocarbon chains

properties of alkanes

• nonpolar, LDFs only

• insoluble in water

• low boiling point

• low reactivity

• formula is CnH(2n+2)

two types of alkanes

straight chain (stronger LDFs) and branched chain (weaker LDFs)

naming branched chain alkanes

• parent molecule is the longest continuous strand of carbons

• branches listed alphabetically, with -yl suffix

• suffix -ane

isopropyl substituent

propyl substituent

isobutyl substituent

sec-butyl substituent

tert-butyl substituent

cycloalkane formula

CnH(2n)

cycloalkane reactivity

greater for larger cycloalkanes (less angle strain)

naming cycloalkanes

• priority carbon goes to first ALPHABETICAL substituent

• direction proceeds to the lowest point of difference

reactions of alkanes

• combustion

• halogenation

• dehydrogenation

Combustion equations

amount of carbons in alkane(n) is the amount of CO2 produced, (3n + 1)/2 is the amount of O2 consumes, (n+1) H2O produced

halogenation reactions (substitution reactions)

UV light is used to knock a hydrogen off an alkane and replace it with a halogen (F, Cl, Br, I) to form a halogenated alkane and H(halogen)

dehydrogenation reactions

2 adjacent hydrogens are removed, consuming the halogen and releasing 2H

alkenes

hydrocarbons with double bonds between carbons

alkynes

hydrocarbons with triple bonds between carbons

naming alkenes

• parent molecule is longest continuous carbon chain CONTAINING double bond

• number location of double bond before parent molecule name

• name substituents alphabetically

• suffix -ene

• if there are multiple double bonds, label both, and indicate number with prefix di-tri-tetra- -ene

naming alkynes

• parent molecule is longest continuous carbon chain CONTAINING triple bond

• number location of triple bond before parent molecule name

• name substituents alphabetically

• suffix -yne

• if there are multiple triple bonds, label both, and indicate number with prefix di-tri-tetra- -yne

cis alkenes

both substituents are located on the same side of the double bond, allowing rotation

trans alkenes

substituents are located on opposite sides of the double bond, forcing rigidity

naming cycloalkenes

• double bond gets priority

• decrease numbers if there are multiple

• indicate number of double bonds by prefix di-tri-tetra- -ene

• alphabetize substituents

addition reactions of alkenes and alkynes

an alkene reacts with a hydrogen which is split by a catalyst and double/triple bond breaks replaced with hydrogen

reactions of alkenes and alkynes

addition and halogenation

halogenation reactions of alkenes and alkynes

an alkene reacts with a halogen which is split by a catalyst and double/triple bond breaks replaced with halogen atoms

aromatic hydrocarbons

have delocalized pi electrons creating extra stability ex) benzene

aromatic hydrocarbon reactions (substitution)

substituents replace hydrogens (C-C bonds are too strong)