organic Flashcards

1
Q

Structural vs Chain vs Positional Isomers

A
  • Structural Isomers - same molecular formula but different structures
  • Chain Isomers - main chain length is changed
  • Positional Isomers -exist when position of a branch changes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Dispersion forces definition

A

Defined as weak IMFs that occur in non-polar species due to the formation of temporary dipoles which then induce temporary dipoles in the surrounding species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why do longer alkanes have greater dispersion forces

A

because of increased electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why do straight chain alanes possess stronger dispersion forces than branched alkanes

A

Their shape allows maximum surface contact between the molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does cis/trans geometric isomerism exist

A

Exists due to inability to rotate around the double bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why are alkanes dispersion forces slightly more stronger than alkenes

A

due to stereochemistry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Aldehydes functional group + atoms + suffix

A

Functional group: -CHO (carbonyl - on terminal carbon)
suffix: -al

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dipole-dipole forces definition

A
  • the electrostatic attraction between oppositely charged ends of the overall dipole ,increasing in strength, with the difference in electronegativities between atoms of the molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does longer chain length aldehydes increases melting and boiling points

A

Increases the amount of electrons, increasing dispersion forces which then then add to the strength of the sum total intermolecular forces taking place between aldehyde molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Alcohols functional group + atoms + suffix

A
  • Functional group: -OH (hydroxyl)
  • Suffix: -ol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

H-bonding defintion

A
  • Hydrogen bonding is an extreme form of dipole-dipole forces that only occurs when a hydrogen atom bonded to N, O or F interacts with a non-bonding pair of electrons on another N,O or F - either on the same molecule or different polar molecules
    • H-bonding is due to the highly electronegative negative nature of fluorine, oxygen, nitrogen that have a high charge density due to their relatively small size
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why do primary alcohols have higher BP + MP than secondary alcohols than tertiary alcohols

A

Due to the exposure of the hydroxyl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ketones functional group + atoms + suffix

A
  • Functional group: -C=O (carbonyl - on non-terminal carbon)
    • Double bond oxygen
  • Suffix: -one
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Carboxylic Acid functional group + atoms + suffix

A
  • Functional group: -COOH (carboxyl) on the first carbon
  • Suffix: -oic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why does solubility in polar substances decrease with increasing chain length

A

This is because dispersion forces become more significant, preventing solvation in polar substances thus, they then become more soluble in non-polar substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Amines functional group + atoms + suffix

A
  • Functional group: -NH2 (amine or amino)
  • Suffix: -amine
17
Q

Amides functional group + atoms + suffix

A
  • Functional group: -CONH2 (on starting atom)
    • Double bond oxygen; single bond amine group
  • Suffix: -amide
18
Q

Why is the H-bonding present in amides much stronger than equivalent amines or carboxylic acids (2 reasons)

A
  • Due to a greater number of hydrogen atoms available for hydrogen bonding in an amide compared to an amine or carboxylic acid. Thus, each amide molecule has 3 lone pairs of electrons and two hydrogen atoms that are available for hydrogen bonding
  • Also due to the close proximity of the highly electronegative oxygen atom causes hydrogen atoms from the NH2 group to develop a larger dipole (+) than what would occur on the nitrogen only
19
Q

Esters functional group + atoms + suffix

A
  • Functional group: -COO- (carboxylate - linking two alkane chains)
  • Suffix: -oate
20
Q

What are zwitterions

A
  • The existence of amino acids as a dipolar ion in a solid state or a neutral aqueous solution
    • Has both a positive and negative charge but no net charge
21
Q

What actually happens in a zwitterion on an atomic level

A

In this form, the carboxyl group gives up an acidic proton (leaves a COO-) which is accepted by the amino group (producing -NH3+)

22
Q

3 characteristics of zwitterions

A
  • Zwitterions have much higher melting points - because they possess ionic bonding
  • Dipolar nature of zwitterions also makes them very soluble in water - interacts through ion-dipole interactions
  • Dipolar nature of zwitterions allows them to act as acids or bases and can also act as buffers
23
Q

What are polymers

A

Polymers consist of long chains of repeating smaller units called monomers

24
Q

What can polymers consist of

A

Can consist of long straight chains or they may have side chains that join to other chains (cross linking)

25
Q

Two types of polymerisation reactions that lead to formation of polymers

A
  • Addition Polymerisation - involve small molecule alkenes acting as monomers joining with use of a catalyst to form a polymer
  • Condensation Polymerisation - involve the joining of monomers to produce the polymer and a small molecule such as water or carbon dioxide
26
Q

Proteins definition

A

Natural polymers formed through the combination of a-amino acids

27
Q

Dipeptide vs Polypeptide vs Protein

A
  • When two a-amino acids combine the structure can be referred to as a dipeptide
  • If more a-amino acids add to the dipeptide, it is referred to as a polypeptide
  • In general, if more than 50 a-amino acids are present in a peptide chain - it is referred to as a protein
28
Q

4 Main structures of proteins

A
  • Primary Structure
  • Secondary Structure
  • Tertiary Structure
  • Quantenary Structure
29
Q

Primary structure of protein definition

A

Specific linear sequence of the individual a-amino acids in the protein

30
Q

Type of bonding in secondary structures of proteins

A

H-bonding occurs between a lone pair of electrons from the oxygen in the carbonyl group and the polar hydrogen atom of an amine group

31
Q

A-Helix vs B-pleated sheets

A

A Helix - interactions within peptide chain between carbonyl group and amine group 4 amino acids away, producing coiled helix structure
B-pleated sheets - Interactions between adjacent polypeptides, resulting in hydrogen bonds within the plane of the sheet structure; all amino groups and carbonyl groups are involved in hydrogen bonds in B-pleated sheets

32
Q

Tertiary Structure definition and explanation for formation

A
  • Interactions that occur between the side chains of the a-amino acids in the proteins
    • May be H-bonding, ionic bonding, dipole-dipole forces, covalent bonding or dispersion forces
    • Gives rise to the protein molecule folding (bending and twisting) in such a way to achieve max stability
33
Q

What happens to tertiary structures in aqeous environments

A
  • protein will orient itself such that the hydrophobic side chains are orientated inwards; thus, hydrophilic side chains are orientated outwards with Disulfide bridges (covalent) often exist in the structure
34
Q

Quantenary Structure definition

A

Involves multiple proteins interacting to form larger conglomerate proteins

35
Q

Why is alcohol soluble in water but alkanes aren’t

A
  • The total alcohol-water forces (dispersion forces, dipole-dipole forces, H-bonding) are strong enough to overcome the total alcohol-alcohol (dispersion forces, dipole-dipole forces, H-bonding) and water-water (dispersion forces, dipole-dipole forces, H-bonding) forces, thus they are miscible
  • Alkanes are non-polar molecules with only dispersion forces
  • Thus, the total alkane-water forces (dispersion forces) are not strong enough to overcome the total alkane-alkane forces (dispersion forces) and water-water forces (dispersion forces, dipole-dipole forces, H-bonding), thus the substances are not miscible
36
Q

Explain why ethanal is soluble in water while octanal is not

A
  • The total ethanal-water forces (dispersion + dipole-dipole + H-bonding) are strong enough to overcome the total ethanal-ethanal (dispersion + dipole-dipole) and water-water (dispersion, dipole-dipole + H-bonding) so they are miscible
  • Octanal is a larger molecule than ethanal with more electrons so stronger dispersion forces
  • So the total octanal-water forces (dispersion, dipole-dipole + H-bonding) are not strong enough to overcome the total octanal-octanal (dispersion, dipole-dipole) and water-water (dispersion, dipole-dipole + H-bonding ) forces