Topic_3-Mole_Concept

St. Agnes Academy, Inc.

Junior High School

Teacher: Mr. Joji A. AndesDate: November 25-29, 2024

Topic: Mole Concept

Content Standard

Learners demonstrate an understanding of the mole as a unit that quantitatively measures the number of very small particles of matter.

Performance Standard

Learners apply concepts and principles learned to analyze the percentage composition of different brands of two food products.

Learning Competencies: Mole Concept

  • Use the mole concept to express mass of substances.

Specific Learning Objectives

At the end of the lesson, students should be able to:

  • Acquisition:

    • Define mole concept and its use in chemistry through a three-column table.

    • Use the mole concept to express the number of substances through drill and practice.

  • Meaning-Making:

    • Infer that mole relationships are important to quantify elements and understand this through an exit pass.

  • Transfer:

    • Solve problems involving mass and mole relationships through a problem-solving activity.

References/Links

  • Textbook: Chemistry: Exploring Life Through Science Third Edition

  • Other: Aquino, MD. et al. (2020) Science Links 9 Revised Edition, Rex Publishing, Inc.

Materials Needed

  • Pen

  • Paper

  • Laptop

  • PowerPoint

  • Calculator

  • Marker

Teaching Strategies

  • Guided Inquiry

  • Hands-On Learning

  • Inquiry-Based Learning

  • Collaborative Learning

  • Research-Based Learning

  • Values Integrated Discipline

  • Community Stewardship

  • Global Awareness

Introduction to the Mole Concept

In everyday life, quantities are often expressed in terms such as dozen (12), case (24), or ream (500). The mole serves a similar function for counting particles, namely atoms and molecules, which are too small to be counted directly in typical ways.

Definition of a Mole

A mole is a unit in chemistry that contains exactly 6.02 x 10^23 particles, known as Avogadro’s number. This number was named after the Italian scientist Amedeo Avogadro, who contributed to the understanding of gases and the quantity of particles.

Number of Particles in One Mole of Substance

Substance

No. of Particles

1 mole of S

6.02 x 10^23 atoms of S

1 mole of Cu

6.02 x 10^23 atoms of Cu

1 mole of NaCl

6.02 x 10^23 formula units of NaCl

1 mole of CaCO3

6.02 x 10^23 formula units of CaCO3

1 mole of glucose (C6H12O6)

6.02 x 10^23 molecules of C6H12O6

Weighing Atoms and Mole Concept

Measuring the mass of a single atom or molecule directly poses significant challenges due to their diminutive size. Instead, chemists use Molar Mass, defined as the mass in grams of one mole of a substance, which is numerically equal to its atomic mass. This connection allows for meaningful calculations involving chemical reactions and formulations.

Example:

For example, the molar mass of ascorbic acid (vitamin C, C6H8O6) is calculated as follows:

Component

Atomic Mass (g)

No. of Atoms

Total Mass (g)

C

12.01

6

72.06

H

1.00

8

8.00

O

16.00

6

96.00

Total Molar Mass

176.06 g/mol

Calculation Involving the Mole Concept

To calculate the mass of a substance based on the mole concept, the following formula is used:

  • Formula: n = m / MWWhere: n = number of moles, m = mass in grams, MW = molar weight in g/mol.

Example Problem:

Given:

  • n = 8.20 mol

  • Molar Weight of Fe: 55.85 g/molRequired: m (mass in grams)

Steps to Calculate Mass:

  1. Identify the formula: n = m / MW

  2. Rearrange to find m: m = n × MW

  3. Substitute the values: m = 8.20 mol × 55.85 g/mol

  4. Calculate: Final Answer: 457.97 g

Conclusion

The mole concept is a fundamental idea in chemistry that facilitates our understanding of matter. It allows chemists to efficiently measure large quantities of extremely small particles, making it essential for studying reactions, compositions, and various aspects of material science.