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Lesson Sequence: Day 2



Day 2: Mass vs number concept, moles, introduction to atomic structure and periodic table, LAB 2.

  1. Class work, discussion
    1. Collect Ch. 3 homework.
    2. Review "dozens" problem with molecular models.
    3. Problem: How can salt solutions be compared on the basis of the number of molecules they contain?

                      "dozen" = 12 of anything

      But a dozen molecules of any kind is such a small mass that their behaviour can not be measured. To be able to measure the behaviour of molecules with most common instruments, a much larger number of them is needed.

                      "mole" = 6.02 x 1023 of anything

      How does a mole of a substance relate to its mass?

              By definition: 1 mole of 12C (6 protons + 6 neutrons) has a mass of 12 grams.

              (This means that 6.02 x 1023 C atoms has a mass of 12 grams)

      Basic ideas of periodic table -


        1   - atomic number =# protons in the nucleus (also = # of electrons)
      H 
      1.008   - atomic mass = the mass of one mole (6.02 x 1023 atoms) of this
          element


    4. Students are to make a reasonable guess as to the structures of the first 20 elements of the periodic table given the information above, a periodic table and the examples below (finish for homework) -

      atom    atomic number     atomic mass  
      (grams/mole)  
     # protons   structure    
    # neutrons    
      # electrons  
    H 1 1.008 1 0 1
    He 2 4.003 2 2 2
    Li 3 6.94 3 4 3
    Be 4 9.012 4 5 4

    (students to continue...)


  2. Do LAB 2.

  3. Homework
    • finish the table
    • finish write-up of LAB 2
    • redo the "dozens" exercise of DAY 1 but substitute "moles" for "dozens". Also, use the periodic table to calculate the mass of each compound given the # of moles in part 3a.

        Example 1: 1 mole H2O       -       2H = 2.016 grams/mole
  1O = 15.999 grams/mole
  H2O = 18.015 grams/mole


        therefore: 1 mole H2O = 1 mole x 18.015 grams/mole = 18.015 grams
        and 5 moles H2O = 5 moles x 18.015 grams/mole = 90.075 grams etc.


DAY 1     DAY 3     DAY 4     DAY 5     Teacher Info



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