Intermolecular forces and phases of matter

The two authors, Catherine Zavacki and Anjana Iyer (we love photos of our authors!)

Throughout the past few years we have incorporated a variety of kinesthetic activities into our classroom instruction that allows the students to be up and out of their seats to learn and review content as well as create class cohesion. Studies have shown that learning through movement allows for implicit learning and offers both teacher and student a stimulating classroom environment, and as a result, provides the novelty and change the brain seeks.¹ Learning through movement also allows for immediate formative assessment. 

This activity reviews Lewis structures and polarity. Beforehand students learned polarity and were introduced to intermolecular forces (IMF) through a variety of phenomenon activities, such as using permanent and washable markers (September 2017 issue of Chem 13 News. This activity also introduces how melting and boiling points of the substances are influenced by polarity and molar mass. This 30-minute activity begins with the students filling in their particular molecule’s structure and polarity information, and the rest of the time there is movement and discussion. We provide the melting and boiling point information. 

We are firm believers that unless it is a summative assessment, fellow students are often the best co-teachers. This activity allows students to move freely and ask their peers for clarification on concepts. It reduces stress and builds confidence and understanding.  After several modifications, this activity has shown to be effective in reinforcing the concept of polarity and determining the phase of matter at different temperatures.  

Objective

Using polarity, intermolecular forces and molar mass, student will kinesthetically develop patterns for melting and boiling points of multiple compounds/elements. 

Setup

1. Prepare a chemical formula card for each student. These cards are easy to make. We put the cards in a plastic sleeve so students can use dry erase markers and cards can be reused. These cards are so simple to make, you can make up a class set for each of your classes. 
2. We make two different class sets:

• halogens and
• hydrocarbons and alcohols.

 ​​If you would like an electronic version of these cards, contact Jean Hein. 

3. Each card has the name of one molecule with four spaces,

• one for the structure,
• one to show the polarity
• one for the intermolecular force and
• one for the melting/boiling points and molar mass.

4.  Prepare three large signs for your classroom — solids, liquids and gases. Hang these state-of-matter signs in separate locations in your classroom.

5.  Prepare temperature signs for the teacher to display (ordered randomly):  -210 ⁰C,      100 ⁰C, 50 ⁰C, 0.0 ⁰C, 22 ⁰C, -100 ⁰C, -60 ⁰C, -15 ⁰C
.

Activity 

You will do this activity twice: once with the halogens and then again with the hydrocarbons and alcohols. 
 

Each student will get one chemical formula card and they will fill spaces in by: 

• drawing the structure,
• showing the polarity,
• identifying its intermolecular force (if the molecule interacts with another of the same molecule)
• and calculating the molar mass.

Then the teacher will hold up a temperature and the students will need to go stand at the location that represents what phase their compound/element would be in at that temperature. You can do this for a few different temperatures.

After you have asked a variety of temperatures, ask the students to line up in one row in order of melting point or boiling point. Once the students are lined up you can ask why they have different melting and boiling points. 

For enrichment, we have listed C₄H₉OH in our suggested compounds because it does not follow the expected pattern.

References

1. T. Lengel and M. Kuczala, The kinesthetic classroom: Teaching and learning through movement, 2010, Thousand Oaks, CA: Corwin.