# Intermolecular Forces Lab

Topics: Surface tension, Liquid, Drop Pages: 3 (486 words) Published: January 29, 2013
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
* 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.

Data:

| Water| Rubbing Alcohol|
Part 1| 5 seconds| 2.5 seconds|
Part 2| Keeps shape. Greater surface tension.| Spreads out. Lower surface tension.| Part 3| Float. Greater surface tension.| Sink. Lower surface...