Module 1 - Intermolecular Forces of Attraction Flashcards
Forces that exists between molecules and influence physical properties. It also governs the motion of molecules.
Intermolecular Forces
Collectively known as “van der Waals forces”
Intermolecular Forces
Type of Intermolecular Forces in which it is the weakest of the intermolecular forces. This is the force between two nonpolar molecules. It tends to be stronger the larger the atom or the molecule.
London Dispersion force
Type of Intermolecular Forces that occurs whenever two polar molecules get near each other. The positively charged portion of one molecule is attracted to the negatively charged portion of another molecule.
Dipole-dipole
Type of Intermolecular Forces that refers to the electrostatic interaction between a hydrogen and a lone electronegative pair of atom.
Hydrogen Bonding
Type of Intermolecular Forces where interaction occurs when an ion encounters a polar molecule. In this case, the charge of the ion determines which part of the molecule attracts and which repels.
Ion-dipole
Strongest to weakest intermolecular force magnitude.
Ionic interactions > Hydrogen bonding > Dipole-dipole interactions > London dispersion forces
All else being equal, stronger intermolecular forces result in _______ boiling points and melting points
Higher
At a constant (a) _______________, vapor (b) ____________ with the (c) ____________ strength of IMF.
a) temperature
b) decreases
c) increasing
Factors that affects Intermolecular Forces
- melting point
- boiling point
- vapor pressure
- viscosity
Properties of Liquids
Refers to the measure of elastic force in the liquid.
Surface tension
Types of Surface Tensions
- adhesion
- cohesion
- capillary action
- meniscus
Type of surface tension that refers to when liquid molecules stick to other surfaces.
Adhesion
Type of surface tension that refers to when liquid molecules stick to each other.
Cohesion
Type of surface tension that refers to when liquid climbs up a small tube (like water going up in a straw).
Capillary action
Type of surface tension that refers to when there is a curved surface of a liquid in a container.
Meniscus
Properties of Liquids
Refers to the distance between particles.
Density
Properties of Liquids
Refers to the measure of liquid’s resistance to flow.
Viscosity
Properties of Liquids
Partial pressure exerted by gas molecules above a liquid when the two states are in equilibrium
Vapor pressure
Properties of Solids
- Molecules form a regular repeating three-dimensional structure.
- Have high melting points due to the uniform IMF acting on the form.
Crystalline solids
Types of Crystalline Solids
Consists of positively and negatively charges held by electrostatic forces. High melting point due to strong ionic bonds.
Ionic Crystals
Types of Crystalline Solids
Atoms are held together in an extensive three-dimensional network by covalent bonds.
Network/Covalent Crystals
Types of Crystalline Solids
Includes noble gases, diatomic elements, and small nonpolar polyatomic molecules.
Molecular Crystals
Types of Crystalline Solids
The crystal solid with the simplest structure: every lattice point is occupied by an atom of the same metal. Usually very dense. The bonding electrons are delocalized over the entire crystal, responsible for the metal’s strength
Metallic Crystals
Properties of Solids
- Molecules can aggregate with no particular order.
- Formed rapidly where the atoms or molecules do not have time to align themselves and may become locked in positions.
Amorphous solids
Refers to the transitions between phases of matter accompanied by the absorbing and releasing of heat.
Phase change
Liquid-Gas Phase Change
Happens when a liquid transforms into gas.
Vaporization or evaporation
When the atmospheric pressure (atm) is exactly 1 atm (at sea level), the temperature at which boiling occurs is called the ________ ________ ________.
Normal boiling point
Liquid-Gas Phase Change
Also known as the measure of strength of intermolecular forces in a liquid.
Molar heat of vaporization
Liquid-Solid Phase Change
Transformation of liquid to solid.
Freezing
Liquid-Solid Phase Change
Reverse of freezing.
Melting
Solid-Gas Phase Change
The process in which the molecules directly form the solid into the gaseous phase.
Sublimation
Solid-Gas Phase Change
Reverse of sublimation. Gas to solid.
Deposition
Summarizes the condition at which substance exists as a solid, liquid, or gas.
Phase Diagram
