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									              IIT/FIELD MUSEUM – High School Transformation Project

                          Lesson: Introduction to the Mole
                            Glencoe Chemistry: Matter and Change
                             Unit 4 The Mole and Stoichiometric
                               Chapter 11 The Mole
                                    Section 11.1 Measuring Matter
                                    Section 11.2 Mass and the Mole

    Context of Lesson
       Taught near the end of the first unit, this lesson teaches students to classify matter as
mixtures, compounds and elements through an analogy. The class should already have talked
through the definitions of matter, elements, compounds, and mixtures.

   Main Goals/ Objectives:
      Students will do activities about the size of a mole and the relationship between moles
and mass. In performing these activities, students will:
    Describe how a mole is used in chemistry.
    Relate a mole to common counting units.
    Relate the mass of an atom to the mass of a mole of atoms.

       Nature of Science: Integrated Theme
      Distinguish observations from inferences, explain that inferences should be based on
       observations, and explain that the development of scientific knowledge involves both
       observations and inferences so scientific knowledge is partially inferential.
      Explain that scientists’ creativity influence their doing inquiry so they may have different
       observations and interpretations of the same phenomena.
      Explain that scientists’ background knowledge influence their doing inquiry so they may
       have different observations and interpretations of the same phenomena.
      Explain that scientific knowledge should be based on empirical data.

       Scientific Inquiry: Integrated Theme
      Explain that scientific investigations all begin with a question, but do not necessarily test
       a hypothesis.
      Explain that there is no single scientific method and provide at least two different
       methods.
      Explain that inquiry procedures are guided by the question asked.
      Explain that all scientists performing the same procedures may not get the same results.
      Explain that inquiry procedures can influence the results of an investigation.
      Explain that research conclusions must be consistent with the data collected.
      Explain that scientific data are not the same as scientific evidence.
      Explain that explanations are developed from a combination of collected data and what
       is already known.

   General Alignment to Standards
   State Goal 11: Understand the processes of scientific inquiry and technological design to
   investigate questions, conduct experiments, and solve problems.
       A. Know and apply the concepts, principles and processes of scientific inquiry.
            ILS 11.A.4a Formulate hypothesis referencing prior research and knowledge
            ILS 11.A.5b Design procedures to test the selected hypotheses.
            ILS 11.A.4c Collect, organize and analyze data accurately and precisely
            11.A.4e Formulate alternative hypotheses to explain unexpected results

   State Goal 12: Understand the fundamental concepts, principles and interconnections of
   the life, physical and earth/space sciences.
       C. Know and apply the concepts that describe properties of matter and energy and the
            interactions between them.
             ILS 12.C.3b Model and describe the chemical and physical characteristics of
                matter.

    Materials
For each group of 2 students:
     “How Big is a Mole?” worksheet
     Pencil
     Highlighter or fine-tip marker

Per class:
    One-mole samples of at least ten elements and four compounds (see note)
    Electronic balances

    Preparation
Measure the mass of fourteen identical transparent containers—zip-top sandwich bags, plastic
vials, etc.—and write the mass of each container on the outside of it. Then measure out exactly
one mole (by mass) of ten different elements and four compounds. (Choose substances that
have molar masses within the range of the student balances’ capacity.) Place one sample in
each container, and write the name and formula on the outside of the container. An example is
given below:




                                     Potassium Chloride
                                     KCl

                                     bag mass: 4.03 g
   Note
Mole Song: Mike Offutt’s CD of chemistry songs, including “A Mole is a Unit,” is available at
http://www.artistsofnote.com/mike/tapes.html

The following is a list of suggested materials, one mole samples of at least ten
elements and four compounds.



                          Element/ Compound                      Mass

                     1    Aluminum (Al)                          27.0g
                     2    Carbon (C)                             12.0g
                     3    Copper (Cu)                            63.5 g
                     4    Iron (Fe)                              55.9g
                     5    Lead (Pb)                              207.2g
                     6    Magnesium (Mg)                         24.3 g
                     7    Nickel (Ni)                            58.7g
                     8    Sulfur (S)                             32.1g
                     9    Zinc (Zn)                              65.4g

                     10   Ammonium Chloride (NH4Cl)              53.5g

                     11   Calcium Chloride (CaCl2)               147.0g

                     12   Calcium Sulfate (CaSO4)                145.2g
                          Magnesium Sulfate
                     13                                          246.4g
                          (Epsom Salt) (MgSO4 · 7H2O)
                     14   Olaxic Acid (H2C2O4 · 2H2O)            126.0g

                     15   Sodium Bicarbonate (NaHCO3)            84.0g
                     16   Sodium Carbonate (NaCO3)               128.0g
                     17   Sodium Chloride (NaCl)                 58.5g
                     18   Sucrose (C12H22O11)                    342.0g
                     19   Water (H2O)                            18.0g
The Lesson

   Bell Ringer
Write on the chalkboard or overhead: “What do the words pair, dozen, and gross have in
common? Write what links these words as well as an example of how each one is used.” Allow
students time to think, pair, and share their responses.

    Activity
Discuss briefly with students the fact that the words pair, dozen, and gross all convey a distinct
number. You know that there are 12 items in a dozen. No matter what the item, a dozen is
equal to 12. A gross is another unit of grouping. There are 144 items in a gross. A score,
another set group, is equal to 20 items. You can have a score of years or a score of rocks, but it
will always be 20 items. There is a word we use in chemistry that similarly means a particular
number: that word is mole and the number it represents is 6.02 x 1023. This number is known
as Avogadro's number. Written in standard notation, that’s 602 000 000 000 000 000 000 000!
To give students a sense of how very large this number is, tell them that a mole of sheets of
paper, stacked up, would reach to the moon eighty billion times! (If you have a recording of a
mole song such as Mike Offutt’s “A Mole is a Unit,” this is a good time to play it for the class!)

Pass out the “How Big is a Mole?” worksheets. Instruct students to make as many dots as they
can in the box on the front during the one minute you will give them to do so. When they have
their pencils ready, tell them to start, then allow one minute for making dots before telling
students to stop. Instruct students to count the number of dots in the box and write down
their dots/minute measurement. To facilitate/speed up the counting process, suggest that
students mark each dot with a highlighter as they count it. Then instruct students to work with
their seat neighbors (in groups of four or so) to find out how long it would take the whole class
to make a mole of dots. (Sample calculations are below.)

If a student can make 303 dots per minute, it will take 3.78 x 1015 years to make a mole of dots!

         6.02 x 1023                                                              3.78 x     1015
1 mole               minute               1 hour       1 day           1 year
         dots                                                                     years
                                          60
         1 mole          303 dots                      24 hours        365 days
                                          minutes

Even if 25 students in the class worked at this rate, it would take the class 1.51 x 10 14 years,
making dots 24-7, to make a mole of dots!

           6.02 x 1023                                                              1.51 x 1014
1 mole                    minute        1 hour          1 day        1 year
              dots                                                                     years
                         7 575
         1 mole                      60 minutes     24 hours       365 days
                         dots
After students have made the calculations and you have reinforced the immensity of
Avogadro’s number, tell them that you have samples of one mole of several elements. Show
them the containers and explain that the mass on the label represents the mass of the empty
container, so they can determine the mass of the contents alone. Do not tell students how you
measured a mole of each element or what the connection is between moles and mass—let
them wonder, for a few minutes, how you counted out all those atoms! Instruct students to
work with a partner and measure the mass of each mole sample and record their data in a data
table. Students are responsible for determining how you counted out a mole of atoms (or
formula units, in the case of the compounds) of each substance. Circulate among students as
they work, asking questions to get a sense of their thought processes. Ask what patterns they
are finding among the masses of the elements, and once they have determined that the mass
of a mole of an element is the same number as the element’s atomic mass, challenge them to
determine what this means about the mass of a mole of a compound.

Once students have finished their measurements, gather the class again at their desks for a
brief discussion of their findings. Allow students to share their discovery that a mole of atoms
of an element has a mass in grams equal to the atomic mass in amu of that element and the
corresponding relationship for compounds. Also, ask students what data from this experience
are based on observations and which are inferences. The numerical data—masses of the
samples—are observations, while the pattern and the relationship between moles and atoms
are inferences. Discuss the importance of both types of data.

   Homework
Read Sections 11.1 and 11.2; do practice problems #1-3, 11, 13, and 15

   Modifications/Accommodations
    To save a bit of time dotting and counting, allow students just thirty seconds for making
     dots, then have them double the number of dots in the box for a dots/minute
     measurement.
    Assign the calculation of how many minutes/mole of dots for homework. Alternatively,
     do the calculation on the board as a demonstration/reminder of factor-label
     conversions.

    Assessment
Students’ responses to the bell ringer, their calculations during the dots activity, their
conclusions during the mass activity, and their discussions with their partners will be observed
by the teacher and contribute to the teacher’s assessment of students’ learning. Their activity
sheets and responses to the section review will also contribute to the assessment.
Introduction to the Mole Model Lesson
Pre Lab Activity: How Big is a Mole?
A mole is 6.02 x 1023 of anything. A mole of donuts is 6.02 x 10 23 donuts, and a mole of
basketballs is 6.02 x 1023 basketballs—and that’s a lot of basketballs! A mole of basketballs
would just about fit into a ball bag the size of the Earth! So just how big is a mole? That’s what
we’re going to find out.

When your teacher instructs you to do so (and not before!), spend exactly one minute making
dots in the box below, as many dots as you can make in a minute.




Now, count the dots. (A highlighter or differently-colored pen may be useful.) What is your dot
making rate in dots/minute? _____________

Working at this rate, how many dots could you make in an hour? _____________________

     ___ dots     60 minute        ____ dots/hr

     minute       1 hour

In a year? ___________________________


     ____ dots 24 hours       365 days    _____ dots/yr

     hour         1 day       1 year

So how long would it take you to make a mole of dots? That’s 6.02 x 10 23 dots!
     ____ dots 1 mole           _____ mole/hour
                 6.02 x 1023
     hour
                 dots


How long would it take to make a mole of dots if your whole class worked constantly at this
rate? __________________


     ____ dots

     hour



Avogadro’s number (6.02 x 1023) is an ENORMOUS number, but it has to be! A mole of copper
atoms would fit nicely in the palm of your hand—about 20 copper pennies. Atoms are so tiny
that we need a huge number of them to work with.
Introduction to the Mole Model Lesson
In the lab, you have the opportunity to measure a mole of several elements. Record the
chemical formula for each element, along with the mass you measure, in a data table below.

Write down any patterns or generalizations you notice about the masses of the mole samples
of elements.

Write any patterns you notice for the compounds.

Write your guess about how your teacher counted out a mole of atoms of each element.
                    Introduction to the Mole Laboratory Activity
                                     Data Table

                                                Mass of
                            Chemical                      Mass of    Mass of
     Sample                                   Sample with
                            Formula                       bag (g)   Sample (g)
                                                bag (g)
1    Aluminum

2    Carbon

3    Copper

4    Iron

5    Lead

6    Magnesium

7    Nickel

8    Sulfur

9    Zinc
     Ammonium
10
     Chloride
11   Calcium Chloride

12   Calcium Sulfate
     Magnesium
13   Sulfate
     (Epsom Salt)
14   Olaxic Acid
     Sodium
15
     Bicarbonate
16   Sodium Carbonate

17   Sodium Chloride

18   Sucrose

19   Water
                    Introduction to the Mole Laboratory Activity
                                     Data Table
                                              Mass of
                         Chemical                       Mass of     Mass of
     Sample                                 Sample with
                         Formula                        bag (g)    Sample (g)
                                              bag (g)
1    Aluminum            Al                 31.8 g         4.8 g   ~ 27.0 g

2    Carbon              C                  16.8 g         4.8 g   ~12.0 g

3    Copper              Cu                 68.3 g         4.8 g   ~ 63.5 g

4    Iron                Fe                 60.7 g         4.8 g   ~ 55.9 g

5    Lead                Pb                 212.0 g        4.8 g   ~ 207.2 g

6    Magnesium           Mg                 9.1 g          4.8 g   ~ 4.3 g

7    Nickel              Ni                 63.5 g         4.8 g   ~ 58.7 g

8    Sulfur              S                  36.9 g         4.8 g   ~ 32.1 g

9    Zinc                Zn                 70.2 g         4.8 g   ~ 65.4 g
     Ammonium
10                       NH4Cl              58.3 g         4.8 g   ~ 53.5 g
     Chloride
11   Calcium Chloride    CaCl2              151.8 g        4.8 g   ~ 147.0 g

12   Calcium Sulfate     CaSO4              150.0 g        4.8 g   ~ 145.2 g
     Magnesium
13   Sulfate             MgSO4 · 7H2O       251.2 g        4.8 g   ~ 246.4 g
     (Epsom Salt)
14   Olaxic Acid         H2C2O4 · 2H2O      130.8 g        4.8 g   ~ 126.0 g
     Sodium
15                       NaHCO3             88.8 g         4.8 g   ~ 84.0 g
     Bicarbonate
16   Sodium Carbonate    NaCO3 . H2O        128.8 g        4.8 g   ~ 124.0 g

17   Sodium Chloride     NaCl               63.3 g         4.8 g   ~ 58.5 g

18   Sucrose             C12H22O11          346.8 g        4.8 g   ~ 342.0 g
19   Water               H2O                22.8g          4.8g    ~18.0g

								
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