CHEMISTRY

• Compounds

  Made up of only one type of molecule (two or more atoms that are chemically bonded); composed of two or more elements, can be separated into simpler substances and elements by chemical methods ONLY
• Ionic compounds

  • Components are a pair of anion group and a cation group; electrons are transferred from the cation to the anion; usually formed when a metal reacts with a non-metal
• Ionic compound


  • NaCl
• Covalent compounds

  • Components are both anion groups; electrons are shared within the bond; formed when two non-metals react with each other
• Covalent compound

  • CO₂
• Metallic compounds

  • Components are both metals; electrons are stored in a "sea of electrons"
• Metallic compound

  • AgNO
• Law of Definite Proportions


  Regardless of amount, a pure compound always contains the same elements in the same proportions by mass
• Law of Multiple Proportions (Dalton's Law)


  When one element combines with another to form one compound, the mass ratios of the elements in the compound are simple whole numbers of each other
• Mixtures


  Made up of two or more different kinds of pure substances; individual properties are retained and can be separated by PHYSICAL methods
• Homogenous mixtures


  • Mixtures wherein only one phase is discernible; with uniform composition and properties throughout, commonly called "solutions; can be separated into their component substances by PHYSICAL processes, such as distillation and crystallization
• Concentration


  Measure of the relative amounts of the components of a solution
• Solute


  The component that dissolves in the solution
• Solvent


  The component that dissolves other components of the solution
• Solubility


  The maximum amount of solute that can be dissolved in a particular solvent under specific conditions; often expressed as a ratio or other measures of concentration; greatly depends on the balance of the intermolecular forces of the solute and the solvent
• Common measures of concentration

  • Molarity (M)
  • Molality (m)
  • Mass Percent
  • Volume Percent
  • Mole Fraction
• Molarity (M)


  Moles of solute / Liters of solution
• Molality (m)

  Moles of solute / kg of solvent
• Mass Percent

  Mass of solute / Mass of solution x 100
• Volume Percent

  Volume of solute / Volume of solution x 100
• Mole Fraction

  Moles of component / Total moles
• Pure substances


  Made of only one kind of substance and has constant properties and composition; CANNOT be physically separated
• Types of pure substances

  • Elements
  • Compounds
• Elements


  • Fundamental substance, made of only one kind of atom; cannot be chemically simplified or decomposed
• Types of elements

  • Metals
  • Non-metals
  • Metalloids
• Metals


  • The number of valence electrons is small; donates electrons during ionic bonding; forms cations when ionized
• Metal

  • Potassium
• Metals

  • Lustrous
  • Ductile
  • Malleable
  • Good conductor of heat and electricity
  • Solid at room temperature
  • Tendency to lose one or more electron
• Non-metals


  • The number of valence electrons is close to completing the octet rule; accepts electrons during ionic bonding; forms anions when ionized; properties are opposite those of metals, liquid or gas or brittle solids at room temperature
• Non-metal

  • Oxygen
• Metalloids


  • Have physical properties of both metals and non-metals; can act as a metal or a non-metal depending on the conditions
• Metalloid

  • Silicon (semiconductor)