GEN CHEM 2

• Kinetic Molecular Theory (KMT) is 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
• Properties of Liquids:

  • Liquids are fluids that can flow and assume the shape of the container
  • Liquid molecules are close together with very little space to move past one another freely
  • Liquids are difficult to compress due to the very little space between molecules
  • Liquids are denser than gases under normal conditions
  • Liquids have a definite volume due to attractive forces holding the molecules together
• Properties of Solids:

  • Solids are rigid and resistant to change
  • Particles in solids are tightly arranged and organized, making them highly dense and incompressible
  • Particles in solids vibrate back and forth
  • Solids have a definite shape, volume, and melting point
  • Solids have a low rate of diffusion and don't mix easily with other substances
  • Types of solids include crystalline solids and amorphous solids
  • Crystalline solids have particles arranged in a crystal lattice and change sharply when heated
  • Crystalline solids can be metallic or ionic crystals, with different properties
• Ionic crystals are compounds made of metals and nonmetals
• Ionic crystals are good conductors of heat in a solid state like NaCl
• Covalent network crystals have extremely high melting points like quartz and diamond
• Quartz will show a well-defined arrangement of atoms
• Covalent molecular crystals contain two or more nonmetals like CH4, NH3, and H2O
• Amorphous solids lack a well-defined arrangement of basic units found in crystals
• Surface tension is the amount of energy required to stretch the surface of a liquid by a unit area
• Liquid molecules with high intermolecular forces have high surface tension
• Capillary action is the attraction between liquid and solid materials
• Cohesion is the intermolecular attraction between the same molecules
• Adhesion is the intermolecular attraction between unlike molecules
• Viscosity is higher in molecules with more intermolecular forces
• Glycerol has the highest intermolecular forces among water, glycerol, and ethanol
• Decane is more viscous than hexane
• Acetone has more molecules turning into a gaseous state at STP condition
• Molar heat of vaporization is the energy required to vaporize 1 mole of a liquid
• Molecules with high boiling points require more energy to vaporize
• Molecules with strong intermolecular forces have low vapor pressure