hydrocarbon – boiling point & refractive index) 2025 Concordia University
LAB REPORT
EXPERIMENT 3:
SIMPLE DISTILLATION: INDETIFICATION OF A PETROLEUM HYDROCARBON –
BOILING POINT & REFRACTIVE INDEX
Name: THI HONG LOAN LAI
Student ID: 40293473
CHEM 221 LAB SECTION 53L
, 1. INTRODUCTION:
This experiment aims to use physical property analysis to identify an unknown hydrocarbon.
The hydrocarbon is not a pure substance; rather, it is a component of a petroleum mixture. The
physical characteristics of several known hydrocarbons are compared with the density, boiling
point, and refractive index of the pure unknown. Although many compounds share similar
chemical characteristics, their distinct structures can give them physical characteristics that help
differentiate them.
The density of a substance is a relationship between its mass and its volume, D = m/V.
Understanding a material's density is essential for many different industries because it can be
used to identify its characteristics, such as whether it will float or sink. In this experiment, we
will compare the density of the sample to the provided known data to determine the identity of
the unknown sample.
The refractive index determines the degree of bending a light beam experiences from one
medium to another. Another way to write it is n = c/v, the ratio of the speed of light in a vacuum
to the speed of light in the medium. There are several uses for refractive indices; the most
frequent one is the difference between liquid samples. One can determine as substance by
matching a refractive index of this measurement with known values.
Distillation is a liquid purification technique that can be used to separate mixture ingredients
if their boiling points are noticeably different. In a distillation, a liquid is boiled in a "distilling
flask," whereupon the fumes leave the apparatus and come into touch with a cool surface in
another part of the machine. As the vapors condense on this cool surface, the condensed liquid—
called the distillate—drips into a reservoir apart from the original liquid. Distillation is, all things
considered, the process of boiling a liquid, condensing the gas, then gathering the liquid
elsewhere. Many industrial processes depend on distillation since it allows components from
complicated mixtures to be separated and purified. For example, in the pharmaceutical industry,
distillation is used to purify and separate active pharmaceutical ingredients from complex
mixtures. [1]
The boiling point of a substance is the temperature at which it transforms from a liquid to a
gas or when its vapor pressure equals the atmospheric pressure. It is a unique physical
characteristic of a compound that can be used to classify or identify various types of materials.
Molecular weight, intermolecular forces, and molecular structure all affect the boiling points of
different compounds.
2. RESULTS:
A list of possible hydrocarbon unknowns is provided [2]: