Lecture 5 - Basic Pharmaceutical Principles

What is a dipole?

A chemical species in which there is a separation of charge; there is a positive pole in one part of the species and a negative pole in another part

What are the strongest intermolecular forces?

Hydrogen bonds

What are the weakest intermolecular forces?

London dispersion forces

What are london dispersion forces?

Extremely weak attractive forces between atoms or molecules caused by the electrostatic attraction between temporary induced positive and negative dipoles

What are the only forces of attraction between nonpolar molecules?

London dispersion

How strong are london dispersion forces?

0.01 to 2.0 kcal/mol

What makes london dispersion forces stronger?

An increase in mass and the number of electrons

What is dipole-dipole bonding?

Intermolecular bonds between two polar molecules

Does H₂O or H₂S have a higher boiling point?

H₂O

Which molecule has a higher boiling point?

Acetone

What are hydrogen bonds?

Bonds shared between one hydrogen and two electronegative atoms (Nitrogen, oxygen, fluorine)

Which molecule has a higher boiling point?

Ethanol

______ bonds cause a higher boiling point.

Stronger

What position on a benzene ring forms the strongest intermolecular bonds?

Para

Which molecule has the highest melting point?

4-hydroxybenzoic acid

Intermolecular hydrogen bonding _______ boiling point and melting point.

Raises

Intermolecular hydrogen bonding between a solute and a solvent _______ solubility

Increases

Intermolecular hydrogen bonding between a solute and a solvent often results in _________ solubility.

Large or infinite

Which molecule has a higher boiling point?

Water

Which molecule has a higher boiling point?

Hexane

Which molecule has a higher boiling point?

Pentane

Stronger molecular forces ______ boiling point.

Increase

Larger sized molecules have a _____ boiling point (compared to smaller molecules with the same functional groups)

Higher

A larger surface area on a molecule ______ boiling point (compared to molecules with the same functional groups and the same number of carbons).

Increases