Amount of Substance and Its Unit, Mole: Connecting the Invisible Micro World to the Observable Macro World

Amount of Substance and Its Unit, Mole: Connecting the Invisible Micro World to the Observable Macro World

Topic Cluster

Chemistry Mole


Ling Wang
Liaison for the MIT BLOSSOMS China Partnership

Cambridge, MA 

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This lesson has been divided into two parts.
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This two-part lesson examines the concepts of “amount of substance” and its unit, “mole”, which are fundamental core concepts in Chemistry. It is designed to develop and optimize learning/teaching strategies to help students understand these two difficult concepts. The key learning objective is to help students understand that “amount of substance” is used as a bridge to connect the invisible micro world to the observable macro world. The materials for the students’ activities are simple and easily obtained, such as beans, kitchen scales, a stack of paper, a ruler and some chemicals that are common in chemistry labs. Teachers can always make changes and prepare the materials according to what they have in their schools. This lesson is designed for two class sessions and each class session is about 45-50 minutes. Before beginning this lesson, students should have prerequisite knowledge about atoms and atomic structure, including the concepts of isotopes and relative atomic mass. They should also know the composition of matter and the meaning of a chemical equation. In addition, they should know how to express a number in scientific notation.

This two-part lesson, along with two other BLOSSOMS lessons, can be used to present a teaching unit on Amount of Substance and Mole. We suggest that the four lessons be used in the following sequence:

  1. Amount of Substance and Its Unit - Mole: Part 1;
  2. How Big Is a Mole: Do We Really Understand Avogadro’s Number?;
  3. Amount of Substance and Its Unit - Mole: Part 2;
  4. Stoichiometry.





  1. 物质的量及其单位-摩尔:第一部分
  2. 摩尔有多大:我们真的理解阿伏加德罗常数吗?
  3. 物质的量及其单位-摩尔:第二部分
  4. 化学计量学

Instructor Biography

Ling Wang is the MIT BLOSSOMS China Partnership Liaison. Her position is to support the communications between the Chinese partners and the BLOSSOMS team. She has Master's degrees in both Chemical Education and Analytical Chemistry, and worked as a high school chemistry teacher in China before coming to the U.S. Because of her academic background and professional experience, Ling also serves as a Chemistry Content Expert and assists in the review of all chemistry-related BLOSSOMS lessons. She enjoys working with high school teachers to develop BLOSSOMS lessons to promote active learning in the classroom.

Additional Online Resources

Wikipedia: Amount of substance
This Wikipedia discussion provides an extremely comprehensive review of the concept, Amount of Substance.

Technology UK: Amount of Substance
This resource, sponsored by Technology UK, presents an excellent overview of Amount of Substance and Mole, including explanations of relative atomic mass, relative formula mass and molar mass.

The mole misunderstood
This excellent resource from Nottingham Trent University in the UK discusses why the concept of Mole is so difficult to teach and highlights common misconceptions held by both students and teachers.

BLOSSOMS video: How Big Is a Mole? Do We Really Comprehend Avogadro’s Number?
The magnitude of the number 6.02×1023 is challenging to imagine. The goal of this MIT BLOSSOMS lesson is for students to understand just how many particles Avogadro's Number truly represents, or, how big is a mole.

BLOSSOMS video: Stoichiometry
The aim of this MIT BLOSSOMS lesson is to relate the concepts of stoichiometry to daily life activities such as baking a cake, production of cars and the chemical reaction in the Haber Process to produce ammonia. The lesson seeks to enhance students’ problem-solving in stoichiometry involving the calculation of the masses of other reactants consumed and other products formed with the aid of a balanced chemical equation, given the mass of a reactant or product in a chemical reaction.