Experimental analysis of Zn-Sn binary diagram and acetone-chloroform azeotrope
Extract
[...] We were then able to determine the melting temperatures of zinc and tin as well as the temperature of the eutectic. At the end of this lab, we observe that the diagram and experimental values are quite similar to the diagram and experimental temperature values. Certain differences can also be explained by the poor reading of temperatures during the tracing of the cooling curves by the table (too early or too late). [...]
[...] For this study, we used the distillation technique, a chemical process allowing to separate different elements constituting a liquid. The separation of these elements will be made thanks to their different boiling temperatures. The purpose of this TP is to determine the boiling temperature of acetone, chloroform, and the azeotrope. This determination will be made using a refractometer that allows us to link the refractive index of our compound to a percentage of Molar Mass, and therefore to the temperature. [...]
[...] Note that all distillation operations will be carried out under the fume hood because it is necessary to avoid inhaling chloroform. We will make a total of 10 additions, following each of them, we will have two samples (the distillate V and the residue L). These samples should not have a volume above 2 cm3. They will be physically analyzed using an Abbe refractometer present in the room. We have an index table that indicates the refractive indices for different compositions of the acetone-chloroform system, this table will allow us to construct our diagram. [...]
[...] For example, to calculate nT0 of 1V: nT0 of 1V = 1.350 - 4.10^-4 (25-34) nT = n read directly on the spectrophotometer T0 = the temperature of the thermometer T = the room temperature We then end up with new refractive indices, so a new table. We will therefore have two curves. Here is the table with the refractive indices corrected to 25 C° and their corresponding % : Cf curves of dew and boiling point We have two curves: one made with the values of n at 34 C° on the refractometer (the first table) and one, "corrected", with the values of n of the refractometers converted to 25 C°. [...]
[...] Next, we wait for the temperature to stabilize, we note this temperature precisely, it will be our temperature for addition 1 (for 1V and 1L). Then, we take a first quantity of distillate that we will eliminate. Then, we take a second quantity of distillate that we will store in flask 1V. Finally, we take a quantity of residue that we will store in flask 1L. For the 2nd, 3rd, 4th, 5th, 6th addition : We first add to the acetone successively and 21 cm3 of chloroform through an opening of the three-necked flask (15 for the 2nd / 25 for the 3rd etc.). [...]
