Spaces Between Molecules

INTRODUCTION

This experiment illustrates that liquids contain spaces between the molecules.

MATERIALS

• Isopropyl alcohol
• Water
• Food coloring
• 2 100 mL graduated cylinders

WHAT TO DO

1. Designate one of the graduated cylinders the measuring vessel and one the receiving vessel.
2. Measure 50 mL of water in the graduated cylinder designated for measuring and pour it into the cylinder designated for receiving.
3. Add a drop of food coloring.
4. Measure 50 mL of isopropyl alcohol in the measuring graduated cylinder. Add the isopropyl alcohol to the graduated cylinder that contains the colored water and mix. Observe the total volume of the water-isopropyl alcohol mixture.

QUESTIONS

1. What is the final volume of the solution in the 100 mL graduated cylinder that was used as a receiving vessel?
2. Explain what happened when the two solutions were mixed.

SUMMARY

There are spaces between the molecules of liquid water. The alcohol molecules fit between the molecules in the water solution. This causes the final volume of the mixture to be less than the sum of the initial volumes.

SOURCE

"Unseen Movement in Chemistry for Every Kid." Janice Van Cleave, John Wiley, 1989. ISBN: 0-471-62085-8

© S. Olesik, WOW Project, Ohio State University, 2000.