AP Chem Intermolecular Forces and Solutions

Kinetic Molecular Theory

explains gas behavior assuming particles are constant, random, perfectly elastic motion; have negligible volume/IMFs; and KE is proportional to temperature in K

How do the phases compare with respect to kinetic energy?

solid → gas, low KE → high KE

At room temperature, why aren’t all substances in the same phase?

all substances are held together with their own unique forces

Intermolecular forces

attractive forces between molecules; determines many bulk properties of substances such as boiling pt, melting pt, viscosity, surface tension, vapor pressure, etc.

Intramolecular forces

attractive forces within molecules; forces lead to bonding; generally much stronger than intermolecular forces

Ion-dipole forces

intermolecular force; a strong electrostatic attractive force between an ion and a polar molecule (e.g. ions hydrated by water molecules)

van der Waals forces

intermolecular force; exist among molecules (no ions involved); only involves dipoles

Dipole-Dipole forces

van der Waals force; a medium strength electrostatic attractive force between two polar molecules; strength depends on the severity of the dipole; stronger dipole leads to a greater dipole-dipole attraction