Summary

In this lesson, students will learn about gas chromatography by comparing it to paper chromatography. Students will analyze gas chromatography data to learn more about the chemicals present in e-cigarettes. Finally, students will take the knowledge they learned to create an infographic. Students will post their infographic publicly to make a positive impact in their community.

Grade Level

High School

NGSS Alignment

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

• HS-PS1-3: Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.
• Scientific and Engineering Practices:
  • Developing and Using Models
  • Analyzing and Interpreting Data
  • Engaging in Argument from Evidence
  • Obtaining, Evaluating, and Communicating Information

Objectives

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

• Analyze the relative polarity of molecules through the lens of chromatography, specifically gas chromatography.
• Rank the polarity of molecules and use their ranking along with a chromatogram to identify unknown molecules.

Chemistry Topics

This lesson supports students’ understanding of:

• Chromatography
• Identifying an unknown
• Separating mixtures
• Polarity
• Intermolecular forces
• Molecular structures

Time

Teacher Preparation: 10 minutes
Lesson: 60-90 minutes

Materials

• Student handout
• Access to the internet for research
• Poster supplies (paper, markers, glue, etc.) and/or printer (to print out electronically-made posters)

Teacher Notes

• Prerequisite Knowledge Needed:
  • Before completing this lesson, students should be familiar with paper chromatography, polarity, and intermolecular forces (hydrogen bonding and London dispersion).
  • Students will need to be able to determine which molecule is more polar by analyzing a molecular structure.
  • If you would like your students to apply their knowledge of intermolecular forces to the answers in the lesson, they can but it is not necessary. It depends on what level you discuss chromatography with your students.

• Possible Lesson Sequencing:
  • This lesson can be paired with many existing AACT resources.
  • Paper chromatography is a very popular topic in the high school chemistry classroom. This activity builds on students’ prior knowledge of paper chromatography and polarity to understand gas chromatography and e-cigarettes.
  • Before completing this lesson consider using other AACT paper chromatography labs and activities like:
    • Using Paper Chromatography to Separate the Pigments Found in Ink
    • Chemicals, Chromatography, and Crime!
    • T-Shirt Chromatography
    • Candy and Leaf Chromatography
    • Animation Activity: Separating Mixtures (Chromatography at time 4:55)
  • Additionally, this lesson can be paired with the Gas Chromatography-Mass Spectrometry Landmark lesson to learn even more about the applications of the instrumentation.
  • An Answer Key document has been provided for teacher reference.

• Additional Vaping Information:
  • Before or after the activity, students can read the December 2019 ChemMatters article, “Vaping: What You Need to Know” article to gain additional knowledge about the chemistry of vaping.
  • Data for this activity was modeled after Qualitative Analysis of E-Cigarette Liquids using GC-MS published by Agilent Technologies.
  • Below are vetted websites from healthcare professionals you may suggest for students to use for research and see examples of infographics:
    • CDC: Electronic Cigarettes
    • CDC: Quick Facts on the Ricks of E-Cigarettes for Kids, Teens, and Young Adults
    • TheTruth.com
    • Truth Initiative
    • NIH: Smokefree Teen
    • NIH: National Institute on Drug Abuse
    • The Real Costs: Vapes

• Pacing of Lesson:
  • Below is a suggested pacing of the lesson. Teachers should feel free to modify to fit the needs of their students.
  • Background (~15 minutes):
    • Students can read the background section aloud, in small groups, or individually.
    • Lead a short discussion about what students already know about e-cigarettes. Give students 1-2 minutes to reflect on what they know and want to find out.
  • Part 1 (45 minutes):
  • Students work in cooperative groups of 2-4 on the questions. The teacher should circulate and check in with each group to make sure they understand the progression of concepts.
  • Teachers may want to check the answer to question 1 with each group. Alternatively, a quick full-class discussion could be helpful at this point to make sure everyone understands how gas chromatography works.
  • If you have whiteboards in the classroom, you can ask each group to present some of their answers and reasoning to the class through whiteboard presentations at the end of Part 1.
  • Depending on the level to which you have discussed chromatography with students, answers may stop at a polarity explanation or be expanded to a more in-depth explanation using intermolecular forces concepts.
  • Part 2 (30 min):
    • Students may opt to use Google Slides, Canva, Piktochart, or other infographic websites to create their projects. A sample rubric is provided on the student handout.
    • The goal of the infographic is to empower students to promote positive change in their community by posting their project publicly in a location of their choice (online, bathrooms, hallways, businesses, etc.) However, teachers can decide what is best for their students. Additionally, teachers should work with their school and community to help students post their infographics appropriately and with permission.
    • Example infographics can be found on the website, Stanford Medicine: Vaping Information, Solutions & Intervention Toolkit.
    • Teachers may wish to have students create the infographic individually or in small groups.
    • Some students may be shy about posting their work publicly. If that is a concern, work with the student on finding ways to make them comfortable by offering that they can work with another peer, post in a more private location, or present their project to a trusted adult.
    • Students will work at different paces depending on creativity, interest, artistic ability, etc. It’s suggested to allow 30 minutes of in-class time for this portion of the lesson but encouraged to allow students to finish at home or during a study hall if needed.