Organic Chem - Arkanes, Arkenes, Arkynes, Aromatic Hydrocarbons

organic compounds

All compounds that contains carbon

• Various types of compounds ranging from simple carbon chains to more complicated molecules

exceptions to identifying organic compounds

carbon monoxide, carbon dioxide, hydrogen cyanide (HCN)

sys for naming organic compounds developed by

IUPAC (Union of Pure & Applied Chemistry)

• international

general naming compounds rules

1. identify the homologous series it belongs to

2. identify the longest chain → provides “root” of compound name which is the ending

3. identify the substituants and branches

4. number in such a way that makes the branch w the first ordered letter in the alphabet have the lowest number possible

5. you are to indicate where each substituent is w its number

6. if there are multiple of a substituent, you must use number prefixes (di, tri, etc)

7. branches should be listed in alphabetical order

homologous series

series of compounds with the same functional group → use order of priority (A functional group is the reactive part of the molecule that affects the compounds chemistry)

as well as the functional group, all homologous series:

• Can be represented by a general formula

• Differ from their neighbour by CH2

• Have varying physical properties

highest priority means

• it is numbered the lowest

• is the ending of the name

hydrocarbons

Organic compounds that contain only hydrogen and carbon

hydrocarbons are divided into

aliphatics (linear), alicyclics (rings), and aromatics (benzene)

aliphatics are divided into

alkanes, alkenes, and alkynes

alkanes

simple hydrocarbons with only single bonds between the carbon atoms

• also known as a saturated hydrocarbon

general formula for alkane

C(n)H(2n+2) → two hydrogens for each carbon and hydrogens at the ends

each alkane is named by adding _____ to the appropriate prefix which is det by

-ane; # of carbons

roots prefixes

1. meth-

2. eth-

3. prop-

4. but-

5. pent-

6. hex-

7. hept-

8. oct-

9. non-

10. dec-

the parent chain is the

longest continuous chain, can be counted from any dir

anything attached to the parent chain is called a

branch or substituant

• if it is a carbon branch, it uses the same root prefixes but ends in “-yl”

although the chains appear to be straight or 2D, there’s acc a _____ angle b/w each carbon

109.5 deg

general naming rules

1. numbers & groups should be separated w a hyphen until it is the last listed group, which sticks to the root

2. numbers for the same group are separated w a comma

no line diagram for

methane or ethane

when halogens are attached as a branch, their names are turned into

flourine → flouro

chlorine → chloro

and so on

cylic alkanes

• otherwise known as cycloalkanes

• when carbon atoms join to make a circle/ a closed loop

• naming them is jus cyclo-root prefix-ane if it is the main chain

• cyclo-rootprefix-yl if it is branch

simplest cycloalkane

Cyclopropane w three carbons

general formula of cyclic alkanes

C(n)H(2n)

structural isomers

Hydrocarbons with 4 or more carbons in the main chain can have structural isomers, depending on where the alkyl group is located

• diff variations → they would have the same chem formula (same number of carbons and hydrogens) but their structure is different (arranged differently)

properties of alkanes

only intermolecular force present is London dispersion forces

• low boiling and melting pt

• boiling pts are related to the length of the chain → longer the chain, higher the b pt

common rxns of alkanes

• do not react with acids, bases, or strong oxidizing agents

• combustion is the main rxn

• smaller alkanes are highly flammable

• but longer chains are difficult to ignite

alkyl halide

halogen as a substituent group (branch)

substituent group

anything that replaces a hydrogen in a hydrocarbon chain

complete rxn vs incomplete

• insufficient oxygen for incomplete, results in some carbon (soot)

numerical prefixes

unsaturated hydrocarbons

hydrocarbon containing either double or triple carbon-carbon bonds

types of unsaturated hydrocarbons

alkenes and alkynes

order of priority

pay special attention to the alkanes stuff

alkenes

contains at least one double bond

alkynes

contains at least one triple bond

general formula for alkenes

C(n)H(2n)

general formula for alkynes

C(n)H(2n-2)

naming alkenes and alkynes

• mult double or triple bonds must have numerical prefixes (diene, triene, triyne) and the locations must be indicated before the “ene” or “yne”

• the first carbon atom involved in a mult bond must have the lowest number (see order of priority)

when you have a double bond b/w carbons, you

cannot rotate the atoms around that bond.

• so you have two poss ways to lay out the atoms surrounding the double bond

stereoisomers

when the molecules have the same chemical formula and structural backbone but have a different arrangement of atoms.

types of isomers

• Cis isomers

• Trans isomers

Trans isomers

have the same groups located on opposite sides of the double bond

• e formation

cis isomers

have the same groups located on opposite sides of the double bond.

• z formation

when naming, cis or trans appears right before

the ENTIRE name of the alkene or alkyne

cis-

trans- (use a hyphen)

reactions of alkenes

Addition Reactions (breaking of the double bond)

types of addition reactions (alkenes)

Halogenation (adding halides)

Hydrogenation (adding hydrogen)

Hydrohalogenation (adding hydrogen halides)

Hydration (adding water)

halogenation

alkene + halogen → haloalkane

Hydrogenation

alkene + hydrogen → alkane

Hydrohalogenation

alkene + hydrogen halide → haloalkane

Hydration

alkene + water → alcohol (water is separated into H and OH)

Markovnikov’s Rule

states that the hydrogen is added to the carbon with the most hydrogen atoms originally bonded to it

Hydrohalogenation and hydration follows this rule

reactions of alkynes

Addition Reactions (breaking of the multiple bond)

types of addition rxns (alkynes)

Halogenation (adding halides (like bromine))

Halogenation (alkyne)

alkyne + 2 halogens → haloalkane

alkyne + 1 halogen → haloalkene

Aromatic Hydrocarbons

An UNSATURATED hydrocarbon that has a ring structure and a bonding arrangement that causes it to be chemically stable

what is the simplest aromatic hydrocarbon

benzene (C6H6)

structure of benzene

Benzene appears to have 3 double bonds, each spaced by a single bond

• The reality is that these bonds all measure out at equal length.

• actual double bonds would measure shorter.

• this means they are not true double bonds

• benzene can be represented in 2 ways (see picture)

if the main branch is a benzene

the root is benzene

if benzene is a branch

it is called a PHENYL

alkyl halides

when a halogen is attached to a carbon chain