Simulation Activity: Balancing Chemical Equations Mark as Favorite (85 Favorites)

ACTIVITY in Polyatomic Ions, Chemical Change, Conservation of Mass, Precipitate, Conservation of Matter, Balancing Equations, Conservation of Mass, Chemical Change, Conservation of Matter. Last updated January 29, 2024.


In this activity, students will learn how to count atoms and how to balance chemical equations using a simulation and games from PhET Interactive Simulations.

Grade Level

Middle School, High School

NGSS Alignment

This simulation will help prepare your students to meet the performance expectations in the following standards:

  • HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
  • HS-PS1-7: Use mathematical representation to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
  • Scientific and Engineering Practices:
    • Developing and Using Models


By the end of this activity, students should be able to:

  • Balance a chemical equation.
  • Understand that the number of atoms of each element is conserved in a chemical reaction.
  • Recognize and explain the difference between coefficients and subscripts in a chemical equation.
  • Translate between the written description of a chemical reaction and a symbolic representation.

Chemistry Topics

This activity supports students’ understanding of:

  • Chemical reactions
  • Balancing Equations
  • Reactants
  • Products
  • Conservation of Matter
  • Chemical formula
  • Coefficients
  • Subscripts


Teacher Preparation: 10 minutes

Lesson: 45 minutes



  • No specific safety precautions need to be observed for this activity.

Teacher Notes

For the Student

Download all documents for this activity, including the teacher guide, from the "Downloads box" at the top of the page.