Lesson Plan: Why is carbon called the duct tape of Life?

Written By: Angie Bartholomay
Grade Level: 10-12

Time Allotment

2-3 50 minute classes

Overview

This activity is a hands on lesson in which students will use their knowledge of bonds to build models and draw Lewis structures for common compounds. By building the models students will be able to visualize an otherwise difficult concept. Using the models, Lewis structures and VSEPR model students will determine the shape or geometry of the molecule.

Carbon_-_Duct_Tape_of_Life_Lesson.doc

Subject Matter

Chemistry

Learning Objectives

  • Students will apply knowledge of bond types
  • Students will build models of common molecules
  • Students will learn to draw Lewis structures
  • Students will learn to determine molecular geometry using the VSEPR model
  • Students will determine molecular polarity
  • Students will identify ways chemistry impact our everyday life

Media Components - Video/Web

http://www.npr.org/news/specials/climate/video

Materials

worksheet, molecular modeling kits or chemsketch software and computers, lecture power point

Teacher Preparation

Run off worksheet, collect molecular modeling sets or download Chemsketch software on the computers and familiarize yourself with how the program works.

Introductory Activities

INTRODUCTORY ACTIVITY - SETTING THE STAGE: MATERIALS: video and molecular modeling set
  1. We have just learned about forces that hold molecules together remember those are intermolecular forces or more specifically chemical bonds.
  2. We have learned that we can use electro-negativity differences to determine bond types and determine dipole moments that exist.
  3. We also have learned how to draw a Lewis Structure.
  4. Today we are going to apply what we have learned as we build models of some common molecules.
  5. As we watch this 1st video clip I want to listen for the answers to the following questions; (put the questions on the board or use the slide in the power point so students can write the questions down)
    1. Why is carbon called the “Duct Tape of Life”?
    2. What are some examples of how chemistry is important to our everyday lives?
  6. Show video; Episode 1

Learning Activities

MATERIALS: molecular model set
  1. When the video is over discuss the answers to the questions from the introductory activity.
  2. Ask the students to open their molecular modeling set. Explain the color scheme for the set or use the power point slide.
  3. Ask the students to select two hydrogen atoms from their set and a wooden dowel which will represent a bond.
  4. Ask the students to look at the hydrogen atom. How many places are there for the hydrogen atom to bond? (1 hole = 1 bond)
  5. Build a hydrogen molecule using the wooden dowel to represent the bond between two atoms. (Show them yours)
  6. Now let’s draw a Lewis structure in the space provided. (Draw the Lewis structure on the board or show the next slide in the power point)
  7. Ask- What kind of bond exists between the atoms?
    1. Nonpolar covalent because the difference in electro-negativity is zero
  8. Is there a dipole moment?
    1. No, there is no positive or negative end to the molecule
  9. What is the geometry?
    1. We will use the VSEPR theory. ( show the slide or use a chart) Since there are only two atoms involved there is only one choice. Linear.
  10. The bonds are non-polar but what about the molecule? Is there a positive region and a negative region? No
    1. The molecule is non-polar
  11. Show episode 2 – Tell the students, continue to list ways that chemistry is important in our every day lives as well as the properties of methane.
  12. What did you learn about methane?
  13. Lets build a methane molecule. What will we need?
    1. 4 hydrogen atoms
    2. 1 carbon atom
    3. 4 bonds
  14. Draw the Lewis structure. What kinds of bonds exist? (polar covalent)
  15. Is there a dipole moment? (Yes carbon has an electronegativity of 2.5, hydrogen 2.1 so the arrow points toward carbon), indicate it with arrows in your structure.
  16. What is the geometry? (tetrahedron)
  17. What is the molecular polarity? Non-polar, so even though the bonds are polar the molecule is non-polar due to is geometry.
  18. This next compound has received a great deal of attention in the media, carbon dioxide. Once again I want you to continue listing ways that chemistry is important in our everyday lives and is carbon dioxide?
  19. Show episode 3. After viewing discuss what is carbon dioxide?
  20. What do we need to build a molecule?
    1. 2 oxygen atoms
    2. 1 carbon atom
    3. chemical bonds
  21. Ok, Let’s build the molecule. In order to complete all of carbon’s bonding places what kinds of bonds will we need? (double bonds with oxygen)
  22. Draw the Lewis Structure and indicate any dipole moments.
  23. What is the geometry? (linear)
  24. Is the molecule polar or non-polar?
  25. Continue building the molecules on the activity sheet, drawing Lewis structures indicating dipole moments where present. Then using VSEPR model determine the geometry of the molecule and the polarity Of the molecules.
  26. Assign each lab group a molecule that they will share with the class So they can keep the model that they built. Explain that when they share with the class you want them to be able to do the following;
    1. drawn the Lewis structure, name bond types & dipole moments
    2. name the geometry and molecular polarity
    3. describe how the molecule is important in their everyday lives

Culminating Activity

  1. Call on each group to present the results they found about each molecule. As each group presents, the rest of the class should be checking the work that they did. These presentations could be media format.
  2. Ask, how many ways were you able to put on you list for ways that chemistry is important in our everyday live?
  3. I am going to ask each group to give a different impact then call on each set of students to list off what they have heard. They can not give one that has already been given by another group. This could be listed on the board, poster or bulletin board.

Cross-Curricular Activity

  1. art – drawing molecules
  2. language arts- writing
  3. speech – group’s sharing results
  4. technology- group sharing or use of chemsketch to build models

Community Connections

Awareness of increasing CO2 levels in the atmosphere and how the chemicals are important in their everyday lives will help make them better stewards of these resources.