```Moles, Moles, MolesPatricia A. Riley              Lincoln Park High School                               2001 N. Orchard Street Mall                               Chicago IL 60614                               (312) 534-8130 ext. 148Objectives:    By the end of this lesson, 10th grade students will be able to:      1.  define a mole and  2.  measure out a mole by mass or volume.Materials:    Teacher demonstration:               colored dot sticker    various stuffed moles, including one that can be ripped in half    cardboard mole labeled with "1 mole = 6.02 x 1023"    paper clips                           overhead projector    test tubes each containing 1 mole of a common substance:  Aluminum wire,      iron filings, water, sodium chloride (NaCl), etc.        Each pair of students:    60 paper clips                    solid aluminum blocks    balance                           metric ruler    Strategy:    1.  Teacher has a sticker on her cheek and cuddles a stuffed mole in her         arms.    2.  Write the word "mole" on the chalkboard.  Ask the students what it         means.  As students suggest the animal, toss the stuffed mole to the         side and say that is not a chemistry mole.  Rip off the sticker and         throw it away when they mention the beauty spot/skin blemish.  Compare         the chemistry mole to a dozen.  Explain that it represents a set group         of things, 6.02 x 1023, just as a dozen is 12 things.  Write this         value on the board both in scientific notation and expanded to show all        the zeros.  Lean the cardboard mole against the chalkboard.    3.  Scatter 36 paper clips on an overhead projector and ask a student to         come up and count them.  Emphasize that a dozen is a method of counting         and grouping objects.  Pick up three stuffed moles and explain that just        as you can have three dozen paper clips, so you can have three moles of         paper clips.  Change the number of paper clips on the overhead to 42 and        repeat the exercise.  Point out that there can be fractions of a mole.          Pick up a fourth stuffed mole that can be ripped in half and suddenly        rip it apart, while telling the class that there can be fractions of a        mole as well.      4.  Hold up a test tube containing one mole of aluminum wire and ask the         class how many atoms of Al are in the tube.  Hold up a test tube with         one mole of H2O and ask how many molecules of H2O are in the tube.        Repeat with the other test tubes.  Remind the class that a mole is a         fixed number of things just as a dozen is.    5.  Give each pair of students a bag of sixty paper clips.  One student is         to count the paper clips as quickly as possible, while the other records        the time in seconds.  Write the times on the chalkboard and then have         the students average them.  Ask the students how long it would take them        to count out a mole of paper clips, helping them set up the proportions:                        60 paper clips     6.02 x 1023
---------------  =  ------------
recorded time        X seconds

and then solve for X.  Have them then convert this answer into minutes,
hours, days, and finally years; do not forget that a year is actually
365.25 days long, hence Leap Year.  Is it reasonable to count out a mole
of paper clips?  Of anything?  No!
6.  Hold up the test tube containing a mole of aluminum atoms and tell the
class that you only needed five minutes to put the mole of atoms into
the tube.  Repeat with the other tubes.  How could this be done?  Remind
the class that the average atomic mass of an atom of each element is
listed in the Periodic Table.  Explain that a mole of each atom happens
to have that same mass in grams.  This is true since atomic masses are a
comparison of each atom to the standard carbon-12 atom:
Example:
If  1 carbon-12 atom      12.00 amus
----------------  =  -----------
1 hydrogen atom      1.0079 amus     then as long as

we have equal numbers of each atom, the ratio of their weights must
be the same.  One mole of carbon-12 atoms just happens to weigh
12.00g, so one mole of hydrogen atoms must weigh 1.0079 grams:

6.02 x 1023 carbon-12 atoms      12.00 grams                          ---------------------------  =  -------------                          6.02 x 1023 hydrogen atoms      1.0079 grams        Ask again how to get a mole of aluminum atoms into a test tube in five         minutes.  Answer:  weigh it out!  How much does a mole of Al weigh?          Have the students check the periodic table.  Repeat with other familiar         elements.                 7.  Give each pair of students a solid aluminum block and a metric ruler.          Have them measure the length, width, and thickness and then calculate         the volume.  What would be the volume of a mole of such blocks?  What         assumptions would we have to make about the blocks in the mole?   Could         we possibly use volume to measure out a mole quickly?  Yes.  The problem         is what is the volume of one atom of each element?  Hold up any two of         the test tubes each of which contains a mole of a substance and have         students note the differences in the volume.  Have them examine the         Periodic Table for atomic volumes; they are not listed.    8.  Which method is easiest then for measuring out a mole:  counting,         weighing, or using the volume?  Take your pick!Performance Assessment:     Each pair of students will be given a sample of copper, nickel, tin, sulfur, or silicon and told that they have 10 minutes in which to measure out a mole of their element.  All samples will be in either pellet or powder form.  Students will have a balance, a metric ruler, a periodic table, weighing paper, and spatula to work with.  They must measure out their mole, show the teacher             the mole as it sits on the balance or metric ruler, and then write a brief description of the method they used.  ```