Intra & Intermolecular forces

Question 1

Intermolecular

Answer 1

interactions taking place between separate molecules.

Question 2

intramolecular

Answer 2

interactions taking place between separate parts of the same molecule.

Question 3

what do intramolecular interactions help biological marcomolecules to have

Answer 3

Intramolecular interactions help biological macromolecules adopt and maintain their three-dimensional structure.

Question 4

what can non covalent interactions be classified as

Answer 4

Dispersion forces
Permanent dipolar interactions
Steric Repulsion
Hydrogen Bond
Ionic interactions
Hydrophobic forces

Question 5

what are non covalent interactions characterised by

Answer 5

Low bond energies
Effective at long distances
Poor directionality, with the only exception of the H-bond

Question 6

what are covalent bond interactions characterised as

Answer 6

High bond energies – Strong bonds
Short distances
High directionality

Question 7

what is a dipole

Answer 7

A dipole is a neutral molecule with an asymmetric internal distribution of charge

Question 8

how can electrostatic interactions be established

Answer 8

Electrostatic interactions can be established between two charges, a charge and a dipole, or a dipole and another dipole.

Question 9

What is an induced dipole

Answer 9

An induced dipole is a temporary dipole created in a non-polar molecule by the proximity of another charged (ion) or polar molecule (dipole).

Question 10

what is steric repulsion

Answer 10

when two molecules approach each other, the electrons on their surfaces will repel each other.

Question 11

what do dispersion forces describe

Answer 11

Dispersion forces describe the force of attraction between the two areas of opposite charge of two temporary dipoles

Question 12

what do the van der walls interactions describe

Answer 12

describe the overall interaction between two species once both attractive dispersion forces, dipolar interactions, and steric repulsion have been considered.

Question 13

what are the features of induced dipole-induced dipole interactions

Answer 13

They are very short lived: dispersion forces last ~ 10-16 s.

They are extremely weak.

They operate over very short distance.

Question 14

what is the aggregation of non-polar molecules in aqueous solutions driven by

Answer 14

The aggregation of non-polar molecules in aqueous solutions is a process driven by entropy.

Question 15

what does the introduction of hydrophobic molecules in an aquious solution do

Answer 15

The introduction of hydrophobic molecules in an aqueous solution disrupts the hydrogen bonding network between water molecules, without forming new strong interactions.

Question 16

when do hydrogen bonds form

Answer 16

1. A hydrogen atom is bonded to an electronegative atom (e.g. O, N, F…)
   
   2. There is another small electronegative atom in the proximity of the hydrogen atom that can share one of its lone pairs

Question 17

Other physical-chemical properties affected by hydrogen bonding include:

Answer 17

Surface tension: the resistance of a liquid to increase its surface area.

Viscosity: liquids that can form hydrogen bonds are usually more resistant to changing its shape or movement.

Capillary Action: ability of a liquid to ascend through a slim tube (capillary).

Question 18

what are aromatic rings

Answer 18

Aromatic rings are flat structures with p/p electrons floating above and below the plane of the ring

Question 19

how can aromatic rings interact

Answer 19

Aromatic rings can interact through an additional set of non-covalent interactions called pi stacking or p-p staking.