mole concwot

Mole Concept Introduction

  • Warm Up: Light review throughout the week.

  • Introduction to Mole Concept:

    • A mole is a term that represents a number, similar to the term "dozen."

    • Example: 1 mole of sodium corresponds to a specific number of sodium atoms.

    • Abbreviation for mole: The term "mole" will be abbreviated as mol (dropping the 'e').

Conversion Problems

  • Conversion Examples:

    • Set up conversion problem (#80): from aluminum atoms to moles.

    • The conversion setup: Aluminum moles will be on top, and the number of aluminum atoms will be at the bottom.

    • Direction of conversion dictated by units: Atoms go to the bottom to signify the division process.

    • Conclusion: In this case, division is performed.

    • Students are encouraged to calculate using a calculator and collaborate with partners on a practice sheet.

  • Practice Sheets:

    • Focus only on the top half of the sheet, avoiding crossed-out problems, while setting up T-bars for calculations.

Avogadro's Number and Atomic Mass Use

  • Use of Atomic Mass:

    • Introduction to next conversion: From moles to grams.

    • Importance of periodic table for conversion factors.

    • Example: Sodium has an atomic mass of approximately 23, which will be used for conversion.

Exercise: Conversion to Moles from Grams

  • Specifically number 81:

    • Convert 11.8 grams of argon to moles.

    • Set up T-bar format with the understanding that the number (40) associated with argon goes with the grams unit, not the moles, when dividing.

  • Additional Practice (#82):

    • Convert given moles of barium to grams using the atomic mass of barium (137).

Advanced Conversion Problems

  • Complex Problem Example (#83):

    • Given 3.78 grams of silver, the goal is to determine the number of silver atoms.

    • Two-step process:

    1. Convert grams to moles using the atomic mass of silver (108).

    2. Convert moles to atoms using Avogadro’s number (approximately 6.022×10236.022 \times 10^{23}).

    • Calculation: Results in approximately 2.11×10222.11 \times 10^{22} atoms.

  • Further Practice (#84):

    • Convert given platinum atoms to grams using the process outlined above.

    • Atomic mass of platinum is 195.

Additional Exercises

  • Exercise Examples:

    • (#88): Given cadmium atoms, follow the model to convert to grams after conversion to moles.

    • Cadmium atomic mass needed for calculations.

    • (#89): Start with 52 milligrams of carbon, convert to grams, and then to atoms.

    • Understand milligram to gram conversion (milligrams divided by 1000).

Conclusion of Chapter 2

  • Wrap-Up:

    • Review of concepts on calculating moles and grams, atoms, and the use of Avogadro’s number and atomic masses in conversions.

  • Exam Information:

    • Special note: The exam will be on March 2—a week following Spring Break.

  • Next Steps: Preparation for Chapter 3 following the exam review next week.