VOLUMETRIC THERMAL EXPANSION

PURPOSE: The purpose of this experiment is the determination of the coefficient of volumetric thermal expansion for a liquid.

EQUIPMENT: Volumetric expansion flask, unknown liquid, stand, Celsius thermometer, beaker, Bunsen burner

PROCEDURE: 1. Fill the flask carefully until the liquid level is just above the lowest graduation. Place it in the water bath, being sure that the bulb is completely immersed, but not allowing the bottom of the flask to touch the bottom of the water bath beaker.

2. Allow the liquid to stand until the liquid level and the water bath temperature have remained constant for 2 minutes. Record the initial temperature and the volume.

3. Use a very low flame to heat the water bath, so that the water temperature does not increase too much faster than the sample liquid temperature. Stirring with the thermometer, heat until the level reaches 0.40-0.50 (about 20 min.) Make the flame even smaller and allow the temperature and the liquid level to remain constant for 1 minute. Measure and record the final temperature and volume. (Warning: the liquid will boil if it reaches 78º C)

4. Compute the volume coefficient of expansion for the liquid, taking into account the expansion of the glass flask. Use a volume coefficient for glass of 3 α = 1.00 x 10-5 ° C-1

5. Compute the % error in ß, using the accepted value (from instructor). Repeat the experiment and calculate the average value.

QUESTION: What measurement or procedure do you consider the largest source of error in this experiment?

Equations

p. 1

Data and Results

Run 1 Run 2

Temperature, initial

Temperature, final

Volume, initial

Volume, final

∆ Temperature

∆ Volume

ß, Coefficient of expansion, (experimental)

ß, Coefficient of expansion, (literature)

Percent Error

p. 2