Lecture 1

Question 1

What are intermolecular forces?

Answer 1

Forces between molecules that decide how molecules behave with each other

These decide the state of matter

Question 2

What are the two main kinds of intermolecular forces?

Answer 2

Repulsive forces which push molecules apart and attractive forces which bring molecules together

These are balanced

The balance of these dictate what state the substance is in

Question 3

What is the role of intramolecular forces?

Answer 3

They Decide what is inside molecules

decide whether a suspension or emulsion is stabilised

Question 4

What is a suspension?

Answer 4

A substance in which there are solid particles suspended in a liquid vehicle

Question 5

What is the importance of suspensions?

Answer 5

We need to be able to stabilise suspensions in order to produce a pharmaceutical product with an accurate dose. If its not stabilised the dose will be inaccurate

Question 6

How can the stabilisation be controlled?

Answer 6

By controlling the forces

Question 7

What is in vivo?

Answer 7

in the body

Question 8

What is vitro?

Answer 8

out of the boy (usually glassware)

Question 9

how can a solid drug be absorbed and travel around the body?

Answer 9

It must first be dissolved in solution

Question 10

Where do repulsive forces originate from?

Answer 10

Every molecule or atom has an electron cloud on the outside, These are negatively charged so if you bring them together they will repel

Question 11

What is the relationship of repulsive forces and distance?

Answer 11

Repulsive forces increase exponentially with decreased intermolecular distance.

Like a magnet, the closer you bring them together, the harder they will push apart

Question 12

What is the importance of repulsive forces?

Answer 12

They are positive energy (see graph)
Bringing atoms closer together increases repulsive force

This stops molecules from crashing into each other

Question 13

What do attractive forces allow molecules to do?

Answer 13

Interact.

It makes matter coherent.

Question 14

Where do attractive forces originate?

Answer 14

Although electron clouds of an atom are negative, the nuclei are positive so there will be some attraction between molecules due to some positive parts and some negative parts

Question 15

What does the attractive forces curve look like?

Answer 15

It is similar, but opposite to the repulsive curve

Question 16

What is the relationship between attractive forces and distance?

Answer 16

As molecules are closer, attraction is stronger

Question 17

Which charges cause attraction?

Answer 17

Opposite charges.

Question 18

Are intermolecular forces stronger or weaker than intramolecular forces?

Answer 18

weaker

Question 19

What are intramolecular forces?

Answer 19

Forces within molecules.

Question 20

What are intramolecular forces stronger than intermolecular forces?

Answer 20

Otherwise the molecule would break apart and change what it is.

Question 21

How much stronger are intramolecular forces compared to intermolecular forces?

Answer 21

about 10x stronger

Question 22

What are the common names of intermolecular forces?

Answer 22

Van der waal forces - be3tween electron clouds in opposite molecules

Ion dipole forces

ion induced dipole forces

Hydrogen bonding

Question 23

What are van der waal forces?

Answer 23

A loosely defined set of forces involving polar molecules in which polar molecues have permanent dipoles e.g. C covalently bonded to O. O is more electronegative so pulls the electrons towards itself. This creates a polar bond, i.e. a permanent dipole

Question 24

What is a polar molecule?

Answer 24

A molecule in which there is an uneven sharing of electrons between atoms due to some atoms being more electronegative than others

Question 25

What is an ion dipole force?

Answer 25

The type of force Where a dipole created by polar bonds is attracted to an ion due to opposite charges

Question 26

What is an induced dipole force?

Answer 26

When a molecule which initially has no charge or dipole is induced by a new ion or dipole molecule by placing it next to it and thereby causing electrons to repel. This results in the first molecule having an induced dipole and will therefore be attracted to the ‘new’ ion or dipole

Question 27

What is hydrogen bonding?

Answer 27

When H is bonded to either F, O or N which are very electronegative. This H-F molecule can then bond strongly to other H-F molecules. The bond between each individual molecule is the hydrogen bond

Question 28

How can an induced dipole force be used to our advantage

Answer 28

I-I is a non polar molecule, but if we bring another molecule closer we can induce a dipole as electrons in the first molecule are repelled from the side closest to the second molecule.
This makes the left side negative and the right side positive resulting in the induced dipole.

I2 dissolves poorly in water, but if you add KI, it will dissociate in water to form I-, which can set up an induced dipole when within close proximity to I2. This will increase the solubility of I2 as it will more happily dissolve as a I3- ion

Question 29

Why is the dissolution of Iodine important?

Answer 29

Iodine has antibacterial and antifungal properties,

It is also useful in a radioactive accident

Question 30

How can Iodine help in a radioactive accident?

Answer 30

Our thyroid hormones contain I in it.
In the event of a major nuclear break down, we can take I2 tablets so our bodies can be saturated with Good I2 (as opposed to radioactive I2) We therefore will not take up radioactive I2

Question 31

How do intermolecular forces determine state of matter?

Answer 31

If intermolecular forces are rigid this results in a solid,

If more movement is allowed between molecules, this results in a liquid