# Balancing Act, Part 1

## Stoichiometry_ Mole to Mole Ratio

Brittany Bowens, Sherry Franklin, Kelsey Willems | Published: June 5th, 2024 by K20 Center

• Grade Level 10th, 11th, 12th
• Subject Science
• Course Chemistry
• Time Frame 105
• Duration 2-3 days

### Summary

This is part 1 of a 3 part lesson. In this lesson, students learn the role of the balanced chemical equation in establishing the stoichiometric relationship between different substances involved in a chemical reaction. This lesson encourages students to reflect on how the coefficients in the balanced equation can be used as conversion factors to relate the moles of reactants to the moles of products, allowing for quantitative analysis and calculations in stoichiometry. Before this lesson, students should be able to read a periodic table in order to calculate the molecular/molar weight of an element/compound. Students should also know how to balance equations and have an understanding of what a mole represents.

### Essential Question(s)

How can the balanced chemical equation be used to determine the mole-to-mole ratio between reactants and products?

### Snapshot

Engage

Students use lotion to determine the importance of having proportional ingredients for a usable product.

Explore

Students organize and decide reactants and products for various scenarios.

Explain

Students watch a video on how to determine the ratio of elements for products.

Extend

Students apply their understanding of how to convert moles of one element/compound to another.

Evaluate

Students demonstrate their understanding of mole to mole conversion using the My Favorite Mistake strategy.

### Materials

• Lesson Slides (attached)

• Mole-y Art handout (attached; one per student)

• I Notice, I Wonder handout (attached; one per student)

• Stoichiometry Mole to Mole Notes handout (attached; one per student)

• Stoichiometry Mole to Mole Notes (TEACHER COPY) handout (attached; optional)

• Mole to Mole Conversion Practice handout (attached; one per student)

• Mole to Mole Conversion Practice (TEACHER COPY) handout (attached; optional)

• My Favorite Mistake handout (attached; one per student)

• 3 hypoallergenic bottles of lotion (The recommend size is 8oz., but you can use whatever size you want. Be sure to adjust amounts of water added in first two bottles)

• Scale or triple beam balance (one per group)

• Red, green, and yellow cups or red, green and yellow construction papers to make cones (one set per group)

• Colored Pencils

• Chalk

• Black Butcher Paper (optional)

• Dry Erase Pocket Sleeves (optional)

• Dry Erase Markers (optional)

### Engage

10 Minute(s)

Use the attached Lesson Slides to follow along with the lesson. Begin with slide 3. Briefly, read aloud the essential question: How can the balanced chemical equation be used to determine the mole-to-mole ratio between reactants and products? Then, move to slide 4 and share the objectives with your students to the extent you feel necessary.

Display slide 5 and introduce students to the “I Notice, I Wonder” instructional strategy and explain how it can help them observe and reflect on their experiences. Pass out the attached I Notice, I Wonder handout to each student. Provide the three lotion samples with different water concentrations to the students. Make sure each student has access to all three samples. Instruct students to apply each sample of lotion to the same area of their skin (arm or back of hand.) Encourage them to leave space on their skin between each sample to avoid mixing them.

Display slide 6 and ask them to record their observations and reflections on each bottle. Give the students a few minutes to complete this task.

Once students have completed their observations and reflections, have them share their observations with the class. Encourage students to discuss their findings and draw conclusions. Inform students (if they haven’t yet discovered on their own) that each bottle has a different concentration of water. Highlight the importance of having a balance of the right ingredients (reactants) for creating a desired product.

### Explore

40 Minute(s)

Organize students into groups of 3-4 and pass out the attached Mole-y Art handout. Inform students that today they are going to create artwork and determine the amount of moles used to produce their artwork. Provide each group with a stack of a green, yellow, and red cups. Have each group stack the three cups and put the yellow cup on top of the stack.

Display slide 7 and instruct students that they will work as a team to complete the pre-work section. Display slide 8 and inform students that as they are working through the pre-work to use the cups to indicate one of the following:

• Green- We are finished.

• Yellow- We are working.

• Red- We need assistance.

After everyone has completed the pre-work, ask students to spend 2-3 minutes brainstorming what they are going to draw and how they will execute it. Review the responses to the pre-work as a class.

Next, move to slide 9 and provide each group with a large piece of black butcher paper or go outside on the sidewalk. Have have them sketch their artwork. Each group member should weigh their chalk and add their individual contributions to the artwork. Inform students they have 15 minutes to complete their artwork and that it must take up at least half of their paper. If working in the classroom, use the timer on the slide to help students keep track of time.

After completing the artwork, have students return to the handout. They will reweigh their chalk and record it in the table. Next, students will need to calculate the mass of chalk used. Students will then move to complete the data analysis questions. Feel free to use the cups to check for student understanding.

### Explain

15 Minute(s)

Display slide 10 and pass out the Stoichiometry Mole to Mole Conversion Notes handout. Go over the following important terms and information on slides 11-14:

• Stoichiometry

• Reactants

• Products

• Balanced Equation

• Coefficient

• Moles

• Molecular Mass

Display slide 15 and go over the steps needed to solve a stoichiometry problem from moles to moles. Next, move to slide 16 to inform students that they will practice the steps by solving the problem used in the video Stoichiometry Made Easy: Stoichiometry Tutorial Part 1 by ketzbook. After watching the video, allocate time for reflection and discussion of misconceptions.

### Extend

30 Minute(s)

Display slide 17. Place students into groups of 3-4. Provide students with the attached Mole to Mole Conversion Practice handout and colored pencils to represent each element. Instruct students that they will first use the colored pencils to assign a color to each element. Next, students will balance out the chemical formula. After balancing, students will use the colored pencils to check their balanced equation by indicating how many colors of each element are available in the reactants and the products. Once students have balanced out the formula, have them move to convert moles to moles in the question that follows.

### Evaluate

10 Minute(s)

Display slide 18. Introduce the My Favorite Mistake instructional strategy and how it can help them improve their problem-solving skills to help build their understanding. Pass out the attached My Favorite Mistake handout.

Explain to students that the slide displays a problem with a mistake. Ask students to answer the following three prompts on their handout:

• What were two things that were done well?

• Where is the mistake?

• What should be done differently?

Encourage students to show all their work and have students turn in their responses after completion.

Next, consider teaching Balancing Act, Part 2: Stoichiometry_Grams to Grams.