Module 4 - Intermolecular Forces Flashcards
Exam 2
Very strong, specialized dipole-dipole interaction
Hydrogen Bonding
What are the strongest hydrogen bonds?
[X—H - - - :Y] strongest when X and Y are N, O, and F
H bond donor vs acceptor
H-bond donors → molecule providing the hydrogen
H-bond acceptor → molecule that attracts the hydrogen
Very strong interaction between a full formal charge and a dipole
Ion-Dipole
Ion-Dipole depends on the
strength of the dipole
Interaction that allows us to dissolve ionic compounds in water
Ion-Dipole
Ionic interactions between a cationic portion and anionic portion
Electrostatic Interactions
Electrostatic Interactions can be effective at _____ distances and persist _____ than other types of interactions
Farther, longer
Covalent bonds are _____molecular interactions
INTRA
Covalent bonds are the _____ interaction
Strongest - limited reversibility; seldom formed
List the intermolecular forces in order of increasing strength
Van der Waals (London Dispersion) Forces
Dipole-Dipole Interactions
Hydrogen Bonding
Ion-Dipole
Electrostatic Interactions
Covalent Bonds - INTRAmolecular
The intermolecular force that occurs in all polar molecules
Dipole-dipole
Dipole-dipole interaction strength depends on ______
Electronegativity - C-O stronger than C-Br
Interaction arising from the formation of induced dipoles between two non-polar molecules (or portions of molecules)
van der Waals (London Dispersion) Forces
What is the weakest intermolecular force?
van der Waals (London Dispersion) Forces
Water is both an ____ and a _____, depends on situation
H-bond acceptor and donor
What is the difference between intermolecular and intramolecular forces?
Intermolecular - between
Intramolecular - within
Define intermolecular forces
Force of attraction that occurs between atoms, molecules, and ions due to their proximity in space to each other
Intermolecular forces are _____ than intramolecular forces
Weaker
Due to large number of interactions, intermolecular forces appear stronger -
but not actually stronger in reality
The magnitude of _____ (real or partial) affects the strength of the attraction
charge - based on electron density
The stronger the attractive forces between the particles, the more they
resist moving or breaking apart
How does distance impact intermolecular forces?
Distance between species affects the strength of the attraction
Closer = stronger
Define polarity
Separation of electric charge along a bond due to differences in the electronegativity of the bonded atoms - electron density not equally shared, creating partial (+) and (-)
What are the non-polar bonds?
C-C and C-H
Polarity is referred to as
electric dipole or dipole moment
The are the 6 applications of intermolecular forces
Surface tension
Capillary action
Viscosity
Receptor-drug binding
Phase changes
Solubility
Define solubility
The ability of a solid, liquid, or gaseous chemical substance (referred to as the solute) to dissolve in solvent (usually a liquid) and form a solution
Substances with similar _____ will be soluble (solid in liquid) or miscible (liquid in liquid)
polarity –> “like dissolves like”
Representation of the changes in the phase of a substance with respect to temperature and pressure
Phase changes
_______ is required to disrupt molecular interactions and thus lead to changes in the states of matter.
Energy
Changes in phase ______ break chemical bonds
do not
Water boils at a ____ temperature in Denver due to pressure changes
Lower - need longer cooking times
The vast majority of drug compounds bind to receptors through ________ rather than through the _______
intermolecular forces
formation of chemical bonds
What determines properties such as efficacy, potency, and, to a limited extent, toxicity?
Receptor-drug binding intermolecular forces
Measure of a liquid’s resistance to flow
Viscocity - The amount of energy necessary to move an object through a fluid
The spontaneous rising of a liquid in a narrow tube or the movement of a liquid up a piece of paper against the pull of gravity
Capillary Action
Capillary action is the result of _____ and _____ forces
cohesive (hold the liquid molecules together)
adhesive (attraction of the outer molecules to the container’s surface)
Why are aneurysms dangerous? Which application of intermolecular forces dose this relate to?
Aneurysm: weakening of vessels - danger is rupture
Capillary action - Blood travels differently through different shapes
Liquid’s resistance to increase its surface area
Surface Tension
To minimize surface area, liquids form _______
spherical drops
The stronger the intermolecular forces, the more ______ required to increase the surface area
energy
How many drops of water can you put on a penny? How?
100, surface tension
