Item Tag: United States

Distillation collection tube, dual 12ml tubes, 24/40 ST inner/male

Wishbone-shaped custom borosilicate (Kimax/Pyrex) glassware for dual volume determination. Each conical-bottom tube has clear white labels from 1 to 12 mL, with graduations every 0.1 mL, and a white label spot. They appear to have been Kimble Kimax heavy-duty glass centrifuge tubes with a spillover capacity of 13 mL or so, fused to a standard taper 24/40 inner/male joint. We can speculate on two possible uses for this item, although there are many possibilities. First, this might have been used to collect spare distillation cuts in a nonstandard configuration requiring a receiving tube with a male joint. Second, and perhaps more interesting, this could be used to determine the number of particles of a nonvolatile solute in a dilute solution of known weight but unknown molecular mass. Raoult’s Law says that nonvolatile solutes lower the vapor pressure of a volatile solvent. If two solutions obeying Raoult’s Law are exposed to the same closed headspace, net solvent transfer will occur until they eventually reach the same concentration. As the closed system reaches equilibrium, the volume in each tube stops changing, and while it can take weeks, this method of molecular weight determination in solution actually works. Ships on the next business day by USPS Ground Advantage (USA only). Item: JT12mL