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Hexane And Toluene Lab Report

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Jessie Nalley
24 October 2017
Sailajah Gukathasan
Fractional Distillation of Hexane and Toluene

Aim/Purpose: The purpose of this experiment is to separate and purify the liquid components of a mixture with a known composition using a technique called fractional distillation. In order to do so, a liquid mixture is separated into three fractions in the first distillation; then, one of the fractions produced is redistilled to increase the purity of the liquid. Since two rounds of distillation occur, the process is termed fractional distillation. Additionally, it is crucial for students to understand the principles of gas chromatography so the purity and percent composition of each fraction can be determined.

Theory: The basis for this …show more content…

Theoretical plates represent the stage in which two phases, such as the liquid and vapor phase of a substance, establish equilibrium with one another. Thus, since the Hickman still has a short column and a complete separation of hexane and toluene cannot be achieved in one cycle, there are two theoretical plates in this experiment: one from the original distillation where three fractions are recovered, and one from the redistillation of one of the fractions to produce more pure portions. This experiment involves the separation of a solution containing hexane and toluene.

These compounds meet the criteria mentioned above since their boiling points are approximately 40°C apart (hexane: 69°C; toluene: 111°C). During the first distillation, the liquid mixture is separated into three fractions. These three fractions must be collected at the specific temperature ranges shown below:

Desired Composition
Temperature Range
Mostly Hexane
60°-70°C
Equal Portions of Hexane and Toluene
75°-85°C
Mostly Toluene
85°-105°C

The phase diagram of hexane and toluene depicts the relationship between temperature and the mole fraction of the mixture, revealing that as the mole fraction of hexane and toluene changes, the boiling point of the mixture changes as well. It is important to note that at any given point, the mole fraction of hexane and toluene must equal 1.0. The graph below displays the changes mentioned above in regards to the phase diagram and the

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