The evaporation of a liquid absorbs energy and cools its surroundings. Such a process is said to be endothermic. You have probably experienced this phenomenon as you stepped from a swimming pool on a windy day. A major factor in determining the rate of evaporation and the resulting cooling is the strength of attraction between the molecules of a liquid. Substances with strong attractions between molecules evaporate slowly and cool slightly during evaporation. In this experiment, you will study temperature changes caused by the evaporation of different alcohols.
Draw structural formulas for alcohols.
Measure temperatures as three alcohols evaporate.
Determine the change in temperature, Δt, for each of three alcohols.
Predict the change in temperature, Δt, for a fourth alcohol.
Determine the change in temperature, Δt, for the fourth alcohol.
Graph the results.
Use the results to make conclusions about intermolecular attractions.
Sensors and Equipment
This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):
Step-by-step instructions for computer-based data collection
List of materials and equipment
Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.