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Classifying Chemical Reactions

K20 Center, Alexandra Parsons, Alex Parsons | Published: May 31st, 2022 by K20 Center

  • Grade Level Grade Level 9th, 10th, 11th, 12th
  • Subject Subject Science
  • Course Course Chemistry, Physical Science
  • Time Frame Time Frame 2-3 class period(s)
  • Duration More 100 minutes


In this lesson, students will be introduced to general types of chemical reactions. They will look for patterns to group similar reactions together, then use that as a way to put academic language to those groups. A basic understanding of chemical reactions and notation is necessary to complete this lesson.

Essential Question(s)

What patterns are present in chemical reactions?



Students watch and discuss a video.


Students group together reactions and do a Gallery Walk of what other students are thinking.


Students are introduced to different reaction types.


Students complete a station lab with multiple types of reactions.


Students participate in a Chalk Talk to synthesize their knowledge.


  • Lesson Slides (attached)

  • Card Sort handout (attached; one set per group)

  • Reaction Lab Student Guide handout (attached; one per student)

  • Reaction Lab Teacher Guide document (attached)

  • Sticky notes or index cards

  • Poster paper

  • Lab supplies (listen in Reactions Lab Teacher Guide document)


Use the attached Lesson Slides to guide the lesson. Transition through slides 3-4 and go over the essential question and learning objectives with students.

Move to slide 5 and review the proper way to set up and identify the parts of a chemical formula. Inform students that they will be watching a video of children reacting to eating chicken feet and that during the video, they should write down what represents the reactants, reaction (yield), and the products. They should also jot down all of the different reactions they notice.

Move to slide 6 and play the “KIDS vs. FOOD – CHICKEN FEET” video and remind students to think about what happens to cause each reaction.

After playing the video, have students discuss their findings about the different reactions that happened with an Elbow Partner. When they are finished, ask partners, "What happened to make each reaction?" Allow students to discuss why the kids in the video were reacting the way they did.

Move to slide 7 and explain that the reactants are the child and chicken feet separately, the actual eating is the arrow, and the product is how the students feel about the chicken feet once they're together.


Display slide 8 and place students into groups of 3-4. Introduce students to the Card Sort strategy and pass out a set of cards from the attached Card Sort handout to each group.

Instruct students to examine the cards and match similar reactions together. If students struggle to get started, ask them leading questions, such as:

  • What do you notice that's the same?

  • What do you notice that's different?

It may be tempting to give students the answers, but resist this as much as possible.

Distribute sticky notes to each group. Ask them to use two sticky notes per reaction group: one to label each group and one explaining why they grouped them the way they did.

Using the Gallery Walk strategy, have each group walk around and view the other groups’ Card Sorts and justifications for their reaction groups. When they are finished, allow students to return to their groups and discuss whether they want to rearrange any of the cards.


Display slide 9 and begin revealing the solution to the Card Sort activity.

Slide 10 includes the solution for the synthesis category of reactions. Have students copy the definition of synthesis into their notes. Then, ask students to compare the solution on the slide to the solution their group came up with.

Optionally, have students physically demonstrate each type of reaction (with their hands or body, for example) before moving on to the next one. Invite students to share their demonstrations with the rest of the class if they are especially proud of it.

Transition through slides 10-16 and repeat this process for each of the different reaction categories.


Display slide 17 and pass out a copy of the attached Reaction Lab Student Guide handout to each student.

Place students into six groups and assign one group to each of the six lab stations. The six stations focus on:

  • Station 1 – single replacement: zinc and hydrochloric acid

  • Station 2 – decomposition: heated copper (II) carbonate with a burning splint

  • Station 3 – combustion: magnesium strip in Bunsen burner

  • Station 4 – precipitation/double replacement: potassium iodide and lead (II) nitrate

  • Station 5 – synthesis: copper and sulfur, must be done in fume hood

  • Station 6 – acid/base: sodium bicarbonate and hydrochloric acid

Have students rotate through each of the six stations and answer all the questions at the end of the lab handout. When everyone is finished, transition through slides 18-23 to provide and discuss the solutions with students.


Display slide 24 and introduce students to the Chalk Talk strategy.

Have students silently walk around the room to each poster and write their answers to the questions. Encourage them to read and respond to their classmates’ answers.

When students have visited and responded to each question poster, have them return to their seats. Use their answers as a formative assessment to see if the students understand the different reaction types.