Intermolecular Forces Lab

Purpose:
The purpose of the lab was to investigate and demonstrate hydrogen bonding and London dispersion bonding in water and rubbing alcohol.

Hypothesis:
I believe water will have the greater surface tension because rubbing alcohol’s density is lower than water’s.

Materials:
* Water
* Isopropyl alcohol (rubbing alcohol)
* Pennies
* Paper clips
* Flasks
* Cups or jars
* Wax paper
* Eyedropper

Procedures:
Part 1: Surface tension and vortex:
* Fill one flask half way full with rubbing alcohol.
* Fill another flask half way full with water.
Caution: Plug the flask to prevent vapors from polluting the room.
* Carefully swirl each flask to create the vortex.
* Stop swirling each flask and time how long the vortex lasts.
* Record the data.

Part 2: Surface tension and droplet shape:
* Use an eyedropper to transfer one drop of water and rubbing alcohol onto the wax paper.
* The liquid with higher tension will not spread out far while lower tension will spread out. * Identify with liquid has the higher tension and record the data.

Part 3: Surface tension and impenetrability:
* Fill a cup or jar with water and another with rubbing alcohol.
Gradually lower down a paper clip into both liquids using a cradle motion with another paper clip. * Identify with liquid can withstand the weight of the paper clip and record the data.

Part 5: Comparing surface tension of liquids:
* Fill a jar to the brim with rubbing alcohol and another with water. * Examine the rim of each jar.
* Carefully add pennies, one by one, into the jar.
* Stop once the liquid overflows. Record the data.
* Clean and wash your hands before leaving your lab station.

Analysis:
The purpose of the lab was to investigate and demonstrate hydrogen and London dispersion bonding in water and in alcohol. Also it was to test liquids that had the greater surface tension. The lab required four different procedures to test the elements. It was determined that water has a greater surface tension and greater intermolecular force. Water was able to last in a longer vortex compare to rubbing alcohol. Also it was proven that it was able to withstand a paper clip’s weight and maintained a compacted shape after putting a drop of water onto a wax paper. Finally water was able to withstand ___ pennies before overflowing when rubbing alcohol only held ____ pennies. After completing all the procedures in the lab my hypothesis was correct. I believe there were no errors during the lab.

Conclusion:
Investigating and demonstrating hydrogen and London dispersion bonding made a clear statement which liquid, water or rubbing alcohol, had the greater surface tension and greater intermolecular force. After completing the lab I was able to conclude water has the greater surface tension compared to rubbing alcohol.