1. Chemistry Semester Review: Compounds: Intermolecular forces: Intermolecular forces: 1.London (dispersion) forces; dipole-dipole forces; hydrogen bonds are the three basic types. 2.Temporary and weak interactions, based on an attraction of opposite charges, between substances. 3.Affect many different physical properties, such as melting and boiling points, solubility in different solvents, vapor pressure. 4.These forces are different than those that hold atoms together in a substance, which we have identified as either ionic, metallic, or covalent bonds.

2. Chemistry Semester Review: Compounds: Intermolecular forces: Intermolecular forces: 1.London (dispersion) forces: Can occur between both polar and non-polar compounds. Weak temporary interactions, based on shift in the density of electron clouds 2.Dipole-dipole forces: Polar molecules only; attraction between the opposite dipoles of polar molecules. 3.Hydrogen bonds: Special type of dipole-dipole force. Hydrogen is bonded to either oxygen, nitrogen, or fluorine.

3. Chemistry Semester Review: Compounds: Intermolecular forces review TABLE: Intermolecular forces review TABLE: TypeExampleMelting Point Boiling Point Vapor Pressure Diagram Dispersion force Hydrogen gas Low High Dipole- dipole Hydrogen chloride gas Medium Hydrogen bond WaterHigh Low