Gold Seal Lesson:
The Mole Concept

Copernicus Education Gateway

Subject:

Science

Grade:

9-12

ICLE Standards:

Mathematics: Use tables and graphs to interpret expressions and equations. Apply the process of mathematical modeling to real-world problem situations. Use computation, estimation, and proportions to solve problems.

Science: Develop an understanding of the structure of atoms. Develop an understanding of the structure and properties of matter.

Performance Task:

Atoms as the basic unit of all matter are extremely small. Only very special scientific instruments can magnify atoms large enough to see them and make an accurate count. These instruments are not common and their use is not widespread. It is extremely important for scientists to be able to measure atoms in concentrations. Knowing the amount of sugar in the blood for example, is important to humans. Too little sugar or too much sugar can cause a person to become seriously ill. Therefore, knowing how to count atoms is extremely important to Faye, who has diabetes. Diabetes is a disease in which a high concentration of sugar in the blood causes a person to become ill. Faye was anxious to learn more about how to measure atoms and moles in an effort to better understand her own disease and take better care of herself. This activity requires you to weigh a given amount of substance, convert its weight from grams to moles and then from moles to atoms, and to compare their estimated volumes.

Materials Needed:

• 10 grams (g) of (Iron(III)oxide), molecular weight = 160 grams/mole

• 10 grams of Sulphur flowers, atomic weight = 32 g/mole

• 10 grams of NaCl (Sodium Chloride, table sale), molecular weight = 58 grams/mole

• 10 grams of Zn Powder (zinc), atomic weight = 65 g/mole

• Electronic balance or triple beam balance

• Weighing paper

• 4 disposable test tubes of same size

• Test tube rack

1. Working in pairs, put ten grams of each of the substances listed above in the materials list into numbered test tubes and place them in a test tube rack.

2. Using dimensional analysis, find the number of moles in five grams of each substance placed in the test tubes.
   
   A given number of grams can be converted to moles using dimensional analysis as shown in the example below.

3. Transform the answers in #2 to scientific notation and convert to atoms using Avoagardro's number.

4. Estimate the number of atoms in 5, 10, 15, 20, 25, and 30 grams of each sample.

5. Construct a bar graph of the estimated volumes of the 4 samples placed in the test tube rack.

6. Construct a line graph of each of the samples with the number of atoms/molecules on the y-axis and the 5 to 30 gram samples on the x-axis.
   
   Optional:
   Research diabetes and hypoglycemia and write a paper that discusses the effects of sugar concentration on the human condition.
   
   Note to the teacher: This activity may be used to integrate algebra learning activities into chemistry and physical science. Concluding this activity, students should have an understanding of the size of a mole, the different volumes of equal number of atoms. Students will also gain skills in converting from grams to moles and from moles to atoms.
   

Knowledge / Skills:

Understand the best procedures for statistical data collection, organization, and display.  (m5)

Use the technique of dimensional analysis to convert units of measure (e.g., convert km/hr to m/min).  (m33)

Know how to obtain accuracy and precision using common measuring devices.  (s33)

Understand the concept and interpretation of the mole and the gram atomic mass, gram molecular mass, and molar volume of a gas.  (s104)

Know methods of indicating concentrations of solutions (e.g., compute the molarity of a solution).  (s110)

Use stoichiometry to compute quantitative relationships implied by chemical formulas (e.g., find the percent composition by mass of an element in a compound and the simplest ratio in which the atoms combine to form a compound) and chemical equations (e.g.

Gather information from a variety of sources, including electronic sources, and summarize, analyze, and evaluate its use for a report.  (ela3)

Use expository writing skills in subjects other than English language arts.  (ela58)

Rubric:

(Material in parentheses refers to the optional part of the task.)

3 Points  =  The student accurately measures the correct mass of each sample. He/she correctly converts grams to moles and moles to atoms. The graphs are complete and accurate. The student demonstrates an understanding of mole concept, dimensional analysis, and functions involving exponents. (The written paper shows that the student is capable of good research and provides a thorough discussion of diabetes, hypoglycemia, and the effects of sugar concentrations on the human condition.)

2 Points  =  The student accurately measures the correct mass of each sample. He/she has difficulty with conversions, but can correctly convert grams to moles and moles to atoms/molecules with coaching. The student is only able to construct the graphs with help. He/she has only a partial understanding of the mole concept, dimensional analysis, and functions involving exponents. (The written paper shows that the student has some difficulty with research and provides only a surface discussion of diabetes, hypoglycemia, and the effects of sugar concentrations on the human condition.)

1 Point  =  The student does not complete the task. His/her conversions are incomplete and/or inaccurate. He/she does not complete the graphs and/or or makes sloppy graphs with major errors. The student shows little understanding of the major concepts in the task. (The student shows no ability to do meaningful research.)

0 Points  =  The student completes little or none of the task and shows no understanding of any of the concepts in the activity. Little effort is applied. (The student makes no attempt to do any research on diabetes, hypoglycemia, or the effects of sugar concentrations on the human condition.)

Keywords:

CHEMISTRY
LAB EXPERIMENTS
MOLECULES
SOLUTIONS
SCIENTIFIC PROCESS

LIFE SCIENCE
DISEASE

Grades:

Kg [] - 1 [] - 2 [] - 3 [] - 4 [] - 5 [] - 6 [] - 7 [] - 8 [] - 9 [X] - 10 [X] - 11 [X] - 12 [X]

ICLE Application:

D

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