A Simple Apparatus for Measuring Thermodynamic Properties Over the past few years we have successfully used the experiment developed by Joncich, Solka, and Bower1 to measure the thermodynamic properties of ammonium earbarnate. However, we have found that the apparatus shown in their article is rather difficult to reproduce and very susceptible to damage during handling and storage. We have found that a modification of their apparatus enables us to overcome these difficu1ties.z Our modifications are shown below. By using a side-armed dropping funnel containing mercury we have found that the sample and apparatus may be degassed and the manometer filled in a single step (see left). This apparatus may now be placed entirely within a 2-3 in. diameter glass tube and water pumped through from an external water bath (see right) or, if a larger cylinder is available, the apparatus may he placed directly into a regulated water bath. Joncich, M. J., Solka, B. H., and Bower, J. E., J. CHEM. EDUC., 44, 598 (1961).
2Although Joncich, et al., suggest the system may be permanently sealed, we have found it beneficial to include a Teflon vacuum s t o ~ c a c kt o remove impurities.
U.5.Naval Academy
J e a n LaRoque
Annapolis, Maryland 21402
Volume 50, Number 9, September 7973 / 603
