An Improvement of the Vapor Density Experiment in the General Chemistry Course The crucial point of this experiment is the observation of the disappearance of the liquid phase. I n our procedure this is made highly visible by dissolving a, negligible weight of Rhod* mine B in the liquid, which imparts a fluorescent orange color. This is easily di~tinguished from the magenta-colored concentric crystalline rings deposited as the liquid evaporates. The class werages of molcculsr weights for seven unknowns were within 5 % of the true value. ROBERT SEIWALD Tnomns GRUHN MELGORMAN OF SANFRANCISCO UNIVERSITY SANFRANCISCO, CALIFORNIA 94117
390
!Journal of Chemical Education
