Which Will Evaporate First?
Description: The evaporation rate of liquid is observed by wiping a cotton ball saturated with the liquid on a chalkboard and observing the smear disappear. Several pairs of liquids with different molecular characteristics are compared.
Source: Journal of Chemical Education
Year: 1987 Vol: 67 Page: 351
Keywords: Evaporation rate, Liquid, Cotton ball, Vapor, Chalkboard, Intermolecular forces
Rating: 
Hazard: Some
- Inhalation hazard
- Acute toxicity hazard
- Carcinogenicity hazard
- Eye irritation hazard
- Organ toxicity hazard – central nervous system
- Flammability hazard
- Chronic toxicity hazard
- Specific organ toxicity – eyes
Effectiveness: Average
- Results observable with guidance
- Mild effects are seen by audience
- Noticeable contrast between behavior of systems
- Time to results is medium
- Some connection from demo to course material
Difficulty: Low
- Simple procedures
- Simple manipulations for most to perform
Safety Precautions:
- Eye protection required
- Gloves required
- Lab coat recommended
- Perform in a well-ventilated area
- ABC fire extinguisher on hand
- No open flames or spark
- Absorbent materials on hand
Class: Intermolecular Forces, Physical Chemistry, Liquids and Solids
Division: General
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