Module 222

• Kinetic Molecular Theory (KMT) is a model used to explain the behavior of states of matter from a microscopic point of view
• KMT helps explain why matter exists in different phases (solid, liquid, and gas) and how matter can change from one phase to the next
• Liquids are fluids that can flow and assume the shape of the container
• Liquid molecules are close together with very little space, making them difficult to compress than gases
• Liquids are denser than gases under normal conditions and have a definite volume due to attractive forces that do not break the molecules away
• Liquids have attractive forces that influence some of their physical properties
• Solids are rigid, resistant to change, highly dense, and incompressible
• Particles in solids are tightly arranged and organized, vibrating back and forth
• Solids have a definite shape, volume, and melting point
• Crystalline solids have particles arranged in a crystal lattice and change sharply when heated
• Types of crystalline solids include metallic, ionic, and covalent network crystals
• Covalent molecular crystals contain two or more nonmetals and soften gradually when heated
• Surface tension is the amount of energy required to stretch the surface of a liquid by a unit area
• High intermolecular forces result in high surface tension in liquids
• Capillary action is the attraction between liquid and solid materials, either cohesion or adhesion
• Viscosity is the resistance to flow in a liquid, with higher intermolecular forces leading to higher viscosity
• Glycerol has the highest intermolecular forces and viscosity among acetone, ethanol, water
• Vapor pressure is the pressure created by molecules escaping from a liquid to a gas state, with weak intermolecular forces leading to high vapor pressure
• Molar Heat of Vaporization (Hvap) is the energy required to vaporize 1 mole of a liquid at a specific temperature
• Higher boiling points indicate stronger intermolecular forces and require more energy to vaporize