chem lesson 7

• Symbol


  Represents one atom of that element
• Symbol


  • Ca = 1 calcium atom
• Subscript


  A number written at the lower right corner after the symbol of an element, indicating the number of atoms of that element in the molecule
• Subscript


  • N2 = 2 nitrogen atoms (bonded together)
• Subscript outside a bracket


  Multiplies all the elements inside the brackets
• Ba3(PO4)2


  • 3 barium atoms
  • 1 x 2 = 2 phosphorus atoms
  • 4 x 2 = 8 oxygen atoms
• Coefficient


  A number written in front of a chemical symbol, indicating the number of atoms of that element
• Coefficient


  • 3 C = 3 carbon atoms (NOT bonded together)
• Coefficient


  A number written in front of a chemical formula, indicating the number of molecules of that compound
• Coefficients


  • 2H2O
  • 3FeSO4
  • 4Cu(NO3)2
• A chemical reaction occurs when new substances are formed
• Reactant


  Substance that reacts
• Product


  Substance that is produced
• Chemical reaction


  • 2H2 + O2 → 2H2O
• Forms of chemical equations

  • Word equation
  • Skeletal equation
  • Balanced chemical equation
• Word equation


  Write the name of each reactant to the left of the reaction arrow and each product to the right of the reaction arrow
• Word equation


  • hydrogen + oxygen → water
• Word equation


  • beryllium chloride + silver nitrate → beryllium nitrate + silver chloride
• Word equation


  • lead (II) nitrate + zinc → zinc nitrate + lead
• Word equations


  • sodium carbonate → sodium + carbon oxide
  • sodium + iron (II) chloride → iron + sodium chloride
  • sodium + chlorine → sodium chloride
  • fluorine + calcium → calcium fluoride
  • sodium hydroxide + sulfuric acid → sodium sulfate + water
  • sodium + calcium phosphate → calcium + sodium phosphate