Chapter 12 Lecture: Intro to Ochem & Alkanes

OSU BIOPHRM 3311

All organic molecules contain one or more ___.

carbon atoms

Carbon is tetravalent - what does this mean?

each carbon atom forms 4 bonds

organic molecules mainly contain ___ bonds.

non-polar covalent

covalent bonds involve…

sharing of e- pairs b/t 2 atoms

when the electronegativity b/t 2 atoms is less than ___ the bond is non-polar covalent.

0.5

4 general properties of non-polar organic compounds: physical state:

mainly exists as gas or liquid

4 general properties of non-polar organic compounds: solubility:

• insoluble or barely soluble in water, but soluble in non-polar solvents such as carbon tetrachloride (CCl4) and chloroform (CHCl3).

• very small molecules tend to be slightly more soluble

4 general properties of non-polar organic compounds: conductivity:

non-conductors b/c they have NO chargeable particles and do NOT ionize

4 general properties of non-polar organic compounds: boiling & melting points:

low boiling & melting points

organic molecules may contain some ___ bonds.

polar covalent

when electronegativity is ___, the bond is polar covalent.

0.5—1.9

what is the common force w/in polar and non-polar molecules?

London Dispersion Forces (LDFs)

define london dispersion forces

• e- are constantly moving and sometimes they temporarily “bunch up” at one end of the molecule, creating temporary dipoles that induce a dipole in a neighboring molecule. the result is a weak attraction b/t molecules.

• LDFs help molecules stick together — especially, non-polar and noble gases)

what is the internal force unique to polar molecules?

Dipole-Dipole Interactions

define dipole-dipole interactions

internal molecular force created due to polar characteristics — creates a permanent dpole w/in the molecule that results in strong attraction b/t neighboring molecules

polar molecules typically exhibit ___ melting points, boiling points, and water solubility in comparison to non-polar molecules of equivalent size.

elevated

Carbon can form ___ covalent bonds.

multiple

Multiple covalent bonds occur when 2 atoms share 2—3 e- pairs, creating a ___, ___ ___ connection b/t atoms.

• stronger

• more stable

Double bond

bond that shares 4 e-

triple bond

bond that shares 6 e-

organic molecules have specific ___.

3D shapes

the ___ and ___ of an organic molecule depends upon the type and number of bonds b/t 2 atoms

• shape

• bond angle

molecular model color code: hydrogen:

white

molecular model color code: carbon:

black

molecular model color code: oxygen:

red

molecular model color code: nitrogen:

blue

molecular model color code: phosphorus:

purple

molecular model color code: sulfur:

yellow

bond angle is measured b/t 2 atoms that share ___.

the same central atom

tetrahedral shape bond type and angle

• single bond

• 109.5 degrees

planar shape bond type and angle

• double bond

• 120 degrees

linear shape bond type and angle

• triple bond

• 180 degrees

Organic molecules often contain some other ___.

• atoms, in addition to C and H

• may also contain N, O, S, P, and halides (F, Br, Cl, I)

what is the term for a group of atoms w/in a molecule that has a characteristic structure and chemical behavior?

functional group

a given functional group tends to undergo ___ in every molecule that contains

• the same type of rxns

• may have higher reactivity or ranking - larger size does not mean a higher ranking or reacivity

T/F: organic compounds are not classified into familial groups.

False; they are — there are 4 families.

how is the complexity of organic compounds primarily determined?

by the functional group is contains, not its overall size or complexity.

what are the 4 major groupings of functional family groups?

1. hydrocarbons

2. Carbon single bonded to electronegative atom

3. Carbonyl group

4. contains sulfur

hydrocarbons

• alkane, alkene, alkyne, aromatics

• contains only H and C

• “An Easy Year’s Rest”.

Carbon single bonded to electronegative atom - which functional groups?

• alkyl halide, alcohol, ether, amine

• all single bonds

• “Happy Aliens Enjoy Astronomy.”

carbonyls

• aldehyde, ketone, carboxylic acid, anhydride, ester, amide

• carbon is seen double bonding to oxygen

• “A Kind Cat Always Eats Apples.”

amide functional group has how many sub-structures?

3

contains sulfur grouping

• thiol, disulfide, sulfide

• the key is that is contains sulfur

• “Thieves Discover Sulfur.”

hydrocarbons groupings

alkane, alkene, alkynes, and aromatic

alkane characteristics

• saturated — all carbons are bonded to 4 groups and cannot add anymore hydrogens

• contain only C-C and C-H single bonds

• carbon backbone can be straight, branched chains, or cyclic/ring

which functional group is technically considered NOT a functional group and why

• alkane

  • no readily reactive bonds

  • contains only C—C and H—C single bonds

  • serves as the backbone of organic compounds

alkene characteristic

bonds with at least one C—C double bond

alkyne characteristic

bones with at least one C—C triple bond

aromatic characteristics

contains a special ring structure known as aromatic ring, which is known for its unique stability

alkene definition

an unsaturated hydrocarbons w/ at least one Carbon double bond

alkyne definition

an unsaturated hydrocarbons w/ at least one Carbon triple bond

what does “unsaturated” mean?

• means we can still add more hydrogens

• we can turn double and triple bonds into single bonds (alkane)

Functional groups always have the ___ number label.

smallest

aromatic compounds definition

• contain a special ring called an aromatic ring

• includes single and double bonds called benzene rings

what are benzene rings known for?

their unique stability

What does “R-group” stand for?

rest of the molecule

what is the purpose of the R-group

abbrv. for structures of large molecules — especially when the interest/importance is placed on something other than the R-group — i.e., a functional group

When there are 2 R-groups present, how is the second one represented?

R’

alkyl halide general formula & definition

• (—C—X)

• contains 1 or more halogens (Fl, Cl, Br, I)

Alcohol general formula & definition

• (—C—OH)

• contains 1 or more hydroxyl groups (OH) bonded to a saturated carbon atom

Ether general formula & definition

• (—C—O—C—)

• contains an oxygen atom bound to 2 R-groups

Amines general formula & definition

• (—C—N=) N can form 2 additional bonds

• contains N bound to C by single bond

what else can an amine be bound to?

a cyclic compound or be a part of a ring structure

Thiol general formula & definition

• (—C—SH)

• —SH attached to a carbon

Disulfide general formula & definition

• (C—S—S—C)

• formed from 2 thiols

• (—C—SH + HS—C— → —C—S—S—C)

what does the disulfide bond between 2 thiols connect?

2 distant regions or 2 molecules together

What happens when the oxidation of 2 thiols occurs?

1. an atom is lost from each of the 2 SH groups

2. removal of H atom (this is oxidation)

3. produce is called disulfide (bond b/t 2 S atoms)

carbonyl groups consists of…

C=O

what is the C in a carbonyl group called

carbonyl carbon

what is the O called in a carbonyl group

carbonyl oxygen

Aldehyde general formula & definition

carbonyl C bonded to 1—2 H atoms

Ketones general formula & definition

carbonyl C bonded to 2 Cs (or R groups)

within aldehyde and ketone groups, carbonyl C forms bonds with H or C, which have ___ electronegativity.

lower

carboxylic acid general formula & definition

• (—COOH)

• the carbonyl C bonds to OH (hydroxyl)

ester general formula & definition

• (—COOR’)

• carbonyl C bonds to an O, which is, in turn, bonded to another C

amides general formula & definition

• (—CON=) N can form 2 additional bonds

• carbonyl C bonds to N

withing carboxylic acids, esters, and amides, the carbonyl C bonds with O or N, which have ___ electronegativity.

higher

In an alkane structural formula, the C atoms form a ___ with H bond to the remaining open bonding sites.

chain or backbone

Alkane general molecular formula

C_nH_2n+2

alkane condensed formula

no visible bonds, but each distinct structured group is written w/ subscript numbers to designate the multiple groups

w/in line structures, any element apart from the hydrocarbon portions are ___.

consistently depicted, along with the H atoms that form bonds w/ these elements.

Methane formula

CH₄

Ethane formula

C₂H₆

Propane

C₃H₈

Butane formula

C₄H₁₀

Pentane formula

C₅H₁₂

Hexane formula

C₆H₁₄

Heptane

C₇H₁₆

Octane formula

C₈H₁₈

Nonane formula

C₉H₂₀

Decane formula

C₁₀H₂₂

isomer definition

molecules with same molecular formal but different arrangement / connectivity of those atoms

structural/constitutional isomers definition

• when different arrangements of atoms (w/in a molecule) result in distinct physical and chemical properties

• same formula, different structure, different connections

No isomeric forms for Alkanes w/ ___ Carbons b/c there is only ___ to arrange the atoms in each formula so that each C has 4 H.

• 1—3

• one way

constitutional isomers are observed in alkanes that contain ___ C atoms.

4 or more

what is an atom or group that takes the place of a H atom in an organic molecule

a substituent

as the number of C ___, the potential for more constitutional isomers also ___.

increases

major differences b/t constitutional isomers of alkanes

1. connectivity of atoms

2. structure/shape

3. melting and boiling points

4. naming

what are the primary intermolecular forces w/in alkanes?

london dispersion forces (LDFs) (van der Waals or dispersion forces)

The strength of london dispersion forces depends upon what?

size and shape of molecules