Gas Chromatography Lab

Perform the following with three 0.05g samples of unknown and the following solvents: methanol, water and toluene

The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.

Me and my lab partner, obtained a mixture of a un known proportion from the instructor and then flow the guide line in our lab manual to separate the mixture by applying the separation method motioned in our lab manual pages 33-40 . In this experiment, the separation methods were decantation,

C. Pour about one quarter of the first unknown packet into the first cup and add

Using elemental analysis to determine the percent mass composition of each element in a compound is the first step in creating an empirical formula. There are many different types of elemental analysis, but in this experiment gravitational analysis and Beer’s Law are used. Elemental analysis is first used to find the moles of each element, then converted to mass, and then the percent mass of the element in the product is found (2).

Copied the observations table in our notebook. Then recorded the mass of the beaker using the balance and wrote down the measured mass in the observation

Analysis: In this experiment, every substance tested positive for at least 1 organic compound. Corn oil tested positive for lipids. Honey and oats tested positive for starch. Honey, apple juice, and unknown 1 tested positive for sugar. Egg white, gelatin, and unknown 2 all tested positive for proteins. So, not a single substance didn't test positive for at least 1 organic compound. All the indicators used in this experiment change color when in the presence of a compound; therefore, they chemically react with the compound. No errors were made during this experiment

To start this experiment, set up the gas collecting apparatus. To start Part A, add approximately 15mL of distilled water to the test tube and record the temperature. Use about half of an Alka-Seltzer® tablet and record the mass. Close the test tube with the stopper with the tubing and tilt the test tube so the water and tablet react. When the reaction is finished, record the volume of CO2 recovered by lining the meniscus of the graduated cylinder up with the water level.

Then we took 8.35mL of salt water and put it in the evaporating dish which we placed over a Bunsen burner until all the water was dried out. The mass of the evaporating dish with the solid was 83.39g which means the mass of the sodium chloride was 0.622g. Next we took the mass and divided it by the volume of the solution which was 8.35mL and got 0.074 as the original concentration. To the get molarity of the salt solution we had to divide the concentration by the mass of the sodium chloride and then multiply by 1000mL to get 1.3M of salt solution. Final thing we had to do was determine the number ions present in 8.35mL so we took 1.3 moles of NaCl and divided it by 1000mL then multiplied by 8.5mL to get 0.01105 number of Na ions and Cl. The data was as I expected for part A because I followed step by step instructions on how to convert from grams to moles and moles to number of molecules and for part B my answer of 1.3 molarity of salt solution matched with key provided on LoudCloud.

Figure 2: Gas Chromatography analysis from the first sample. From top to bottom the peaks are ordered as followed: 3-methylcyclohexanol (A), 1-methylcyclohexanol (B), and 2-methylcyclohexanol

I came to the conclusion that they should appear (Cl, Br, I) from top to bottom respectively. Based on the previous information regarding mass increases as you go down the periodic table I was able to come to this conclusion. I observed that Cl had the least color concentration, then Br, then I had the most. The greater the color concentration, the greater the mass. This observed data let me come to my conclusion.

8. In order confidently determine what substance my “G9R” was I would have to do over the boiling point experiment a couple of more times. I would turn the gas off and take the Bunsen burner away from the apparatus when the stream of bubbles started coming out from the mouth of the capillary tube. This would allow me to correctly determine when the atmospheric pressure was equal to the vapour pressure.

Spectrophotometry is a routine laboratory test that has the added advantage of being able to

GC-MS is an analytical method that separates mixtures into individual components and uses mass spectrometry to identify each component by specific properties. (1) The instrument used for this experiment was a Thermoscientific- Trace 1310 GC-MS. After analyzing the mass spectrums for the major peaks the components were determined to either be aromatic compounds or cycloalkanes. The gas

Next, I observed my Proton NMR which had only one peak. The multiplicity is six. Therefore, I have six hydrogens. Using this information, I was able to conclude that my unknown is