Distillation: Determination of Volatility and Boiling Point

Volatility: Distillation and Determination of Boiling Point

Barongo, Christine Joy A.

Chemistry 31.1- Section BC

Abstract

In this experiment, distillation was used to determine the volatility of an organic compound and to measure its boiling point using a simple distillation process. Researchers also used evaporation method to compare the volatilities of different organic compounds at a normal temperature. Water, the sample that was used in the distillation process was determined to have a low volatility and a high boiling point ranging from 100֯ C to 108֯C based on the experiment. Difference on the appearance of water was noticeable after the distillation which shows that it was purified than the original tap water sample. Five (5) organic chemical samples including Acetone, Methanol, Ethylacetate, 1-butanol, and water was observed in a watch glass to compare its volatility. The result of the experiment shows that the volatility of organic chemicals varies depends on their physical properties and the type of Intermolecular Forces the chemical exhibits. However, some external factors from the environment may affect the results, humidity for example. Distillation is a simple and effective way to measure the volatility and boiling point of an organic compound within a small period of time Separation and purification of liquids in a mixture can also be made possible using this process. Evaporation, a process applied in distillation, can also be perform separately to compare the volatilities of organic chemicals in the absence of heat. However, evaporation may take time when waiting for a non-volatile liquid to evaporate completely.

Introduction

Organic chemicals and compounds possess a distinct physical characteristic that differentiates them form one another. A unique characteristic of an organic chemical compound is the volatility, which quantified by the tendency of a substance to vaporize, and its boiling point, the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid and a turning point for the liquid to transforms into vapor.

The major factor that affects the volatility and the boiling point of organic compounds are the Intermolecular Forces (IMF). IMFs are defined as the set of attractive and repulsive forces that occur between the molecule as the result of polarity of the molecules. Organic compounds may behave according to the IMFs that their molecules exhibit between other molecules. A deep understanding of the Intermolecular Forces will provide a deep understanding on why chemicals have definite physical characteristics and why they behave on a certain manner.

In this experiment, a simple distillation process was used to identify and record the boiling point of a substance, specifically water, which was used as the sample. Distillation also make the substance purified because as the sample undergo evaporation and condensation, it was separated from its residue and other liquid components form the mixture. The concept behind this is due to volatility where the most volatile liquid in the sample mixture will evaporate first and will be separated from the other substance in the mixture.

Following the distillation process, five (5) organic compound samples underwent evaporation process at a normal room temperature to observe and compare its volatilities.

This experiment was done by the BS Biology students of University of the Philippines Visayas Tacloban College as a requirement for their Chemistry 31.1 class. It was held on February 7, 2019 at the Chemistry laboratory.

The purpose of this experiment was:

• To compare the volatilities of different organic compounds
• To demonstrate simple distillation set up.
• To separate the components of a mixture of 2 liquids.

Results

Table 2.1 Volatilities of different substances.

Table 2.2 Simple distillation and boiling point of water

Descriptions:

Original tap water:

Not so clear; with impurities

Residue after distillation:

Residues remain in the distilling flask, leaving the water in the receiving flask purified.

Distillate:

Clear; no impurities

[pic 1]

 Boiling Point range of water: 100֯ C - 108֯ C

Discussion