Simple and Fractional Distillation Post Lab
Abstract:
In this lab, we performed distillation (simple and fractional distillation). Distillation is a
method that can be used to separate a mixture based purify a liquid component from a mixture.
In distillation, a mixture of liquid is heated to its boiling point and is converted to vapor. In this
experiment, two types of distillation were used to separate the liquid mixture (simple and
fractional distillation). Heating the mixture liquid, forces components that have two boiling
points to enter the gas phase. Simple distillation is similar to fractional distillation. In this
experiment, we tried to separate a mixture for both simple and fractional distillation by heating
the mixture. After the experiment, we graphed the simple and fractional distillation to determine
its boiling point. The boiling point is an indicator of the unknown of the mixture. The unknown
for fractional distillation is hexane-heptane. The unknown for the simple distillation is toluene
since its boiling point is 110.6 degrees Celsius.
Observation
1. For fractional distillation, the boiling point of the two unknowns were lower than
the simple distillation. Also, the boiling point was reached faster because
fractional distillation uses up more energy.
2. The second observation is that there was a break in between the condensation
within the tube, indicating that one solvent finished evaporating and the second
started.
3. Lastly, towards the end of our simple distillation was that the remainder of the
solvent maintained a constant temperature of 107 C and did not increase from
there.
Results:
Simple Distillation Curve
Fractional Distillation Curve
Based on the graphs above, I can come to the conclusion that I have the unknown value
of hexane because hexane boiling point is 69 Degrees Celsius. My indicated values show that
hexane levels between the temperatures of 68 degrees and 73 degrees. Those number indications
gave me the notion that my unknown #1 (Simple Distillation Curve Graph) is Hexane. Whereas
for fractional distillation curve my unknown is toluene. The unknown was determine based on
the boiling point. The boiling point was determined by looking at two areas of the graph where
the temperature levels off or stay sturdy. The temperature levels off at around 68 and 73 Degrees
Celsius until it eventually surpassed 75 C and dramatically increased into a constant around
108.5 C, closer to toluene boiling point of 110 C.
Celsius, the unknown is hexane-heptane.
I. Percent Composition: (Volume of fraction / Total volume distilled) x 100
A. Simple Distillation
A. Fractional Distillation
1. (10 mL - 0 mL / 20 mL) x 100 = 50 %
1. (20 mL -12 mL / 20 mL) x 100 = 40%
II. Unknown 1: Hexane
Unknown 2: Toluene
1. Based on the fractional distillation graph, hexane kept a steady level in
temperature around 68 C - 73 C until it eventually surpassed 75 C and
dramatically increased into a constant around 108.5 C, closer to toluene
boiling point of 110 C.
Conclusion:
In this experiment, we did two types of distillation (simple or fractional distillation) to
determine the technique that is better at separating a mixture complex. Based on the data, we
determined that fractional distillation is better at separating mixtures. Both fractional and simple
distillation have advantages and disadvantages. For instance, simple distillation used less energy
than fractional distillation. However, fractional distillation separate liquids more efficiently since
it can separate mixtures with a smaller boiling point. In this experiment, we used the boiling
point of both simple distillation and fractional distillation to indicate the identity and the purity
of the mixtures.
Post Lab Questions
1. Identify the two unknowns. What differences do you notice between the fractional and
simple distillation graphs?
- The first unknown is hexane and the second one is toluene.
- As pictured above, the difference between the simple and fractional distillation is
that fractional has a much steeper curve in its graph. Another difference is that the
graph for fractional distillation starts earlier than the graph for simple distillation:
69 C in comparison to 73 C. However, both graphs ended around the same area
(105-107 C).
2. How do these differences help support the notion that fractional distillation is more
efficient at separating liquids?
- The difference between boiling points of the two solvents in the graph for
fractional distillation indicates that it is a lot more accurate in comparison to
simple distillation. The simple distillation graph is just a curve that does not give
a solid indication of the difference in solvents.
