Top-Rated Free Essay
Preview

Chem

Good Essays
842 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Chem
The Distillation of an Unknown Compound

INTRODUCTION
Distillation is the process heating a liquid to form vapor which is then collected when cooled and separated from the original liquid. The purpose of this experiment was to determine the identity of an unknown substance using simple and fractional distillation. Gas chromatography analysis the components of a mixture by separation of the materials by their different boiling points.
EXPERIMENTAL
The simple distillation apparatus was assembled using a 10-mL round bottom flask, distillation head, thermometer, adapter, thermometer, and condenser as shown in the Figure 1 (below).
A boiling chip was added into the round bottom flask and 7.0 mL of the unknown mixture #2 was added.
Figure 1

The mixture was heated to a boil. The first drop was recorded at 67° C. After the first 0.5 mL of distillate, the vapor temperature at every .5-mL interval was recorded and a graduated cylinder was used to measure the volume. Table 1 shows that the final sample temperature was at 80.5°C.
After we collected 1.0 mL of distillate, this liquid was transferred into a vial and labeled the vial with the group name. After 3.5 mL of distillate was collected in was placed inside of a dry conical vial. Afterward, the remainder of the distillate was collected. This is the final sample. The fractional distillation was setup and this process was repeated using a distillation column. The first drop according to Table 2 was recorded at 70° C. The final sample temperature for the fractional distillation was 79° C.
One microliter of sample was injected into the gas chromatograph. “Typical response factors for the possible components are as follows: hexane (1.50), cyclohexane (1.80), heptane (1.63), toluene (1.41), ethyl benzene (1.00).”
DISCUSSION
Table 1 Simple Distillation Boiling Points | 1st Drop | 67° C | .5 mL | 69° C | 1.0 mL | 71° C | 3.5 mL | 80.5° C |

Table 2 Fractional Distillation Boiling Points | 1st Drop | 70° C | .5 mL | 72° C | 1.0 mL | 82° C | 3.5 mL | 79° C |

Table 3 Parameters on Gas Chromatographer | Column Type | 20% | He Flow Type | 50 L/m | Injector Temperature | 200° C | Detector Temperature | 195° C | Column Temperature | 120° C |

Graph 1

The data shows that the substances in unknown compound #2 had similar boiling points. Between the initial samples of the simple and fractional distillation differed three degrees Celsius. Between the final samples of the simple and fractional distillation differed 1.5 degrees Celsius. Analyzing the natural boiling points of the given known compounds, we saw that the compound hexane was similar to unknown compound #2. Hexane has a boiling point of 69° C and Table 1 shows that the initial sample had a boiling point range of 69° C. Graph 1 shows the results of both simple and fractional distillation trials. Table 3 shows the parameters of the gas chromatographer. Analysis of the Chrom Perfect Chromatogram Report, the simple initial has three peaks, the highest reading at .37 millivolts. This response is indicative of hexane. Analysis of the simple final chart shows that three peaks were made. The two of the highest of the three points were between .39 to .50 millivolts. The fractional initial chromatogram report shows three peaks, however the middle peak was the highest, reaching .39 millivolts. This once again indicates a hexane presence in the unknown. The fractional final, however, only had one peak, and this peak was at .49 millivolts. According to the text, this means that heptane is present in the compound as well. This data presents that there is hexane and heptane in Unknown Compound #2.
CONCLUSION
It was concluded that Unknown Compound #2 was composed of both hexane and heptane. This was concluded by the analysis of the known boiling points and the data collected from both trials. The analysis of the chromatogram reports also confirmed the results.
REFERENCES
Anne B. Padías, Making the Connections: A How-To Guide for Organic Chemistry Lab Techniques. 2nd edition. (Distillation (pp. 141 – 154) Chromatography, general (pp. 162 – 163) Gas Chromatography (pp. 179 – 187))
Answers to Questions 1. Simple distillation is used when the boiling points of two different substances are very different. Fractional distillation is the separation of a mixture of multiple components into its various fractions according to the difference in their boiling temperatures. a.) Hexyl acetate and butyl acetate- Simple distillation should be used for these two compounds because their boiling points are very different. b.) Hexanol and cyclopentanol- Fractional distillation should be used because there is a small difference of boiling points between these two compounds. 2.

3. (a)In a vacuum distillation system, boiling occurs when the vapor pressure of a liquid surpasses the ambient pressure. Once the pressure drops, the boiling point decreases, and the liquid is quickly sucked from the distillation flask through the condenser into the flask, and then into the pump. (b) (1 atm = 760 torr) Vapor pressure is higher than atmospheric pressure, so the boiling point would be higher.

References: Anne B. Padías, Making the Connections: A How-To Guide for Organic Chemistry Lab Techniques. 2nd edition. (Distillation (pp. 141 – 154) Chromatography, general (pp. 162 – 163) Gas Chromatography (pp. 179 – 187)) Answers to Questions 1. Simple distillation is used when the boiling points of two different substances are very different. Fractional distillation is the separation of a mixture of multiple components into its various fractions according to the difference in their boiling temperatures. a.) Hexyl acetate and butyl acetate- Simple distillation should be used for these two compounds because their boiling points are very different. b.) Hexanol and cyclopentanol- Fractional distillation should be used because there is a small difference of boiling points between these two compounds. 2. 3. (a)In a vacuum distillation system, boiling occurs when the vapor pressure of a liquid surpasses the ambient pressure. Once the pressure drops, the boiling point decreases, and the liquid is quickly sucked from the distillation flask through the condenser into the flask, and then into the pump. (b) (1 atm = 760 torr) Vapor pressure is higher than atmospheric pressure, so the boiling point would be higher.

You May Also Find These Documents Helpful

  • Good Essays

    Ap Chemistry Lab Report

    • 678 Words
    • 3 Pages

    A 125 mL flask was obtained. The square of aluminum was fashioned over the flask by laying the foil over the mouth and folding the sides down. A pin was then obtained and was used to poke a tiny hole in the center of the aluminum cap.…

    • 678 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    Using 22 mL of t-Pentyl alcohol and 50 mL of 37.3% concentrated HCl, a mixture was created and swirled in a 125 mL separatory funnel. After the solution had been mixed for…

    • 1041 Words
    • 5 Pages
    Powerful Essays
  • Good Essays

    The distillation procedure is initiated by gradually heating the mixture until it reaches the temperature of the liquid with the lower boiling point. This liquid then turns into a vapor and leaves to mixture and is collected by the set up apparatus. In fractional distillation a vigreux column is used. This provides for surface area for condensation to occur. At each condensation event the vapor is enriched in the low boiling point component and the liquid is enriched in the high boiling point component. The surfaces where condensation occurs are called theoretical plates. Separation is more efficient when there are more theoretical plates. Therefore, fractional distillation is more efficient in separating than simple distillation. Another new technique was gas chromatography. Gas chromatography is used to separate volatile components of a mixture. First, a small amount is draw up into a syringe and the contents of the syringe are placed into a hot injector pot of the gas chromatograph. The components of the mixture evaporate into the gas phase inside the injector. A carrier gas flows through the injected and pushed the…

    • 395 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    Orgo Lab 5

    • 539 Words
    • 3 Pages

    This experiment was carried out as described in Class Pak. The heat source power was set to 3 for fractional distillation and to 2 for simple distillation. For both processes, aluminum foil was wrapped around the heat source and flask to trap the heat and speed up the process.…

    • 539 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Fig: The chart shows the reagents used in the laboratory experiment and information regarding the solvents.…

    • 1090 Words
    • 5 Pages
    Good Essays
  • Good Essays

    O Chem

    • 729 Words
    • 3 Pages

    40ml of an equimolar mixture of cyclohexane and toluene was obtained and transferred into a 100ml round bottomed boiling flask which contained boiling chips. The distilling column was packed with metal sponge and the height was measured in centimeters and recorded. The distillation apparatus was assembled and a heat mantle was set. Several vials were used as fraction receivers. The vials were labeled, 1-4, and weighed prior to adding the liquid mixture and after the liquid was added. The temperature was recorded before adding heat in order to begin distillation (20º C). The temperature was recorded prior to each distillation fraction and after each 2ml of distillate which was recorded in table 1. The system was turned off and cooled down letting the remaining condensed vapor drain into the round bottomed flask. This sample was transferred by pipette into a vial…

    • 729 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Orgo Lab 2

    • 496 Words
    • 3 Pages

    Experiment II involved two kinds of distillation techniques: simple and fractional. Simple distillation was done to separate ethyl acetate—which has a usual boiling point of 77º—from a less volatile component, while fractional distillation was done to distinguish an ethyl acetate/n-butyl acetate mixture, which has boiling points of 77º and 125 º, respectively.…

    • 496 Words
    • 3 Pages
    Good Essays
  • Better Essays

    The table above shows three different fractions that my group and I gathered during our distillation process. It shows volume at a certain temperature in which it distilled. Fraction #1 shows the first 2mL that was acquired. These couple of mL were thrown out due to a possibility of impurities present. Fraction #2 shows 8 mL of what most likely should be cyclohexane. Fraction #3 is the remaining, toluene, that was last to distill.…

    • 744 Words
    • 3 Pages
    Better Essays
  • Good Essays

    Background: Distillation consists of heating a liquid until it vaporizes, and then condensing the vapor and collecting it in a separate container. Distillation is used to separate mixtures of liquids that either have different boiling points, or that have one component that does not distill. There are many types of distillation, each of which has a distinct purpose. Steam distillation is used to isolate volatile substances that have high boiling points. When two immiscible liquids are distilled together, the amounts of each component in the distillate are constant. Also, the boiling point of the mixture is lower than that of either of the individual components. This is because the components do not have compatible intermolecular forces, and so the component in lesser concentration will form “bubbles”, like oil droplets in water, weakening the overall intermolecular forces in the mixture, and thus lowering the boiling point. This process allows high- boiling compounds, which can decompose before they boil if heated alone, to be distilled at temperatures below 100°C. Once the liquid mixture is heated to its boiling point, the liquid is converted to vapor. The vapors, richer in a more volatile component, are then condensed into a separate container.…

    • 635 Words
    • 3 Pages
    Good Essays
  • Good Essays

    The Simple and Fractional distillation experiment was divided into two parts. We split up the procedure in this experiment. My group did the simple distillation and we received the Fractional distillation from another group in class. In this experiment, we examined the effectiveness of fractional and simple distillation to determine which is more successful at extracting a pure sample. This experiment was very successful. We are able to determine the success of the experiment but calculating refractive index of both types of distillation.…

    • 274 Words
    • 2 Pages
    Good Essays
  • Better Essays

    Another technique used for this experiment is gas chromatography (GC). GC is the separation of compounds between a stationary and a mobile phase. GC can also be referred to as vapor-phase chromatography (VPC) and gas-liquid chromatography (GLC). The sample enters the GC at the injection port. Two components A and B are different, they will stick on the absorbent and there is separation (VPC). Some of the absorbents are coated with a liquid phase. Different components of the…

    • 1878 Words
    • 7 Pages
    Better Essays
  • Good Essays

    fraction can be taken from the bottom of the distillation column or unit, but is often taken from a…

    • 987 Words
    • 4 Pages
    Good Essays
  • Good Essays

    In this experiment we aim to demonstrate that we can separate two volatile compounds from a mixture due to the different chemical properties of each compound. We will accomplish this by a separation procedure known as distillation, which relies on each compound having a distinct and separate boiling point. Our pure products will be analyzed with gas chromatography to determine the success of the distillation.…

    • 692 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Chemistry

    • 708 Words
    • 6 Pages

    Which reagent(s) would serve as the basis for a simple chemical test that would distinguish between benzene and cyclohexene?…

    • 708 Words
    • 6 Pages
    Satisfactory Essays
  • Good Essays

    The degree of separation is determined by the difference of boiling points of the two liquids. Distillation of two liquids having a difference in boiling points of 100°C or more separate more efficiently. This experiment showed a simple distillation apparatus could provide good results of separation for two miscible liquids that had a greater difference in boiling…

    • 1450 Words
    • 6 Pages
    Good Essays