Summary

In this activity, students work in pairs to classify and balance chemical reactions. The partners will begin the activity by coaching one another through the initial questions, and then will take turns completing the remaining questions.

Grade Level

High School

NGSS Alignment

This activity 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.
• Scientific and Engineering Practices:
  • Using Mathematics and Computational Thinking

Objectives

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

• Correctly classify the type of chemical reaction from a given chemical equation.
• Differentiate between five types of chemical reactions, including: synthesis, decomposition, single replacement, double replacement, and combustion.
• Properly balance a chemical equation using coefficients.

Chemistry Topics

This activity supports students’ understanding of:

• Chemical Reactions
• Classification of Reactions
• Balancing Equations

Time

Teacher Preparation: minimal
Lesson: 20 minutes

Materials

• Student Handout

Safety

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

Teacher Notes

• To learn more about this activity, read the associated article, It Takes Two: Partner Work in the Chemistry Classroom, featured in the May 2024 issue of Chemistry Solutions.
• This activity is an example of “Pass the Paper,” (fully described in the associated article), this protocol can be used during student-centered work time.
• It’s suggested to start with a warmup question, such as: List three examples of everyday chemical reactions.
• Next, engage the whole class in a discussion by proposing the question: If we had to categorize these chemical reactions, how would we do so? What categories could we come up with?
• Depending on student ability and prior knowledge, teachers may need to complete direct instruction, or guided notes prior to beginning the activity.
• Then pass out the partner worksheet—one copy per pair of students. The partners should determine who is “Partner 1” and who is “Partner 2”.
• It’s suggested to begin the worksheet by directing Partner 1 to complete the first question while being coached on how to do so by Partner 2. Next, Partner 2 does the second question on the worksheet, and this time is coached through the question by Partner 1.
• Then the partners take alternating turns doing the remaining questions, until the worksheet is completed.
• It’s important to explain that two sets of handwriting should be seen on the paper, in order to emphasize that no individual student can simply complete the work on their own.
• For more details about using this strategy as well as other related information such as grading partner worksheets, refer to the associated article, It Takes Two: Partner Work in the Chemistry Classroom.
• An Answer Key document has been provided for teacher reference.