Investigating the Reaction Between Bromine and Cyclohexane
By adding bromine to a mixture of Cyclohexane and water, and placing
the mixture under a bright light and shaking from time to time,
Hydrogen Bromide is formed. This reaction is shown below:
[IMAGE]C6H12 + Br2 C6H11Br + HBr
When the bromine has all reacted and the red colour has gone, the
hydrogen bromide can be titrated with sodium hydroxide. This reaction
is shown below:
[IMAGE]HBr + NaOH NaBr + H2O
From this titration I can then work out the HBr formed per mole of
Bromine.
Results of my experiment
------------------------
Class results.
Group Number
Mass of Br2 (g)
Titre (cm3)
1
0.99
32.50
2
0.94
29.80
3
1.03
32.60
4
1.04
34.20
5
1.17
35.70
6
0.94
31.25
7
0.95
30.50
8
1.04
32.50
9
1.10
32.20
Average
1.02 to 2dp
32.36 to 2dp
Working out the mean averages
-----------------------------
To work out the mean averages I used the following formula:
Sum of column / number of groups
My results- with raw data
Original mass of stoppered flask (g)
Mass after Bromine was added
(g)
Mass of Br2
(g)
Initial burette volume
(cm3)
Final Burette volume
(cm3)
Amount of NaOH added
(cm3)
136.78
137.81
1.03
100
67.4
32.6
Using the results
-----------------
Bromine
I used a mass of 1.03grams of Bromine.
I arrived at this amount by weighing the volumetric flask without the
bromine added then I weigh the flask with the bromine added. The
different between which was 1.
This experiment was divided into two main steps. The first step was the addition of bromine to trans-stilbene. Trans-stilbene was weighted out 2.00g, 0.0111mol and mixed with 40ml of glacial acetic acid in 100ml Erlenmeyer flask on a hot bath. Pyridinium hydrobromide perbromide of 4.00g, 0.0125mol was added carefully into the flask.
Procedure: Anisole (0.35mL, 0.0378mol) was obtained and placed in a pre-weighed 25 mL round bottom flask, along with 2.5 mL of glacial acetic acid and a magnetic stir bar. Then the reaction apparatus was assembled, the dry tube was charged with conc. sodium bi sulfate, the 25 mL round bottom was attached to the apparatus, and 5 mL of Br2/HBr mixture was obtained and placed in the round bottom. The reaction took place for 20 minutes. An orange liquid was obtained and placed in a 125 mL Erlenmeyer flask along with 25 mL of water and 2.5 mL of conc. Sodium bisulfate soln. The solution was then placed in an ice bath to precipitate and then the solid product was filter in a Buchner funnel. These crystals were then re-dissolved minimum amount of hot solvent (heptane) and recrystallized. Once a dry product was obtained, a melting point was established (2,4-Dibromoanisol mp 55-58 C) and percent yield was established (52%).
Cu (aq) + 2NO3 (aq) + 2Na+ (aq) + 2OH- (aq) → Cu(OH)2 (s) + 2Na+ (aq) + 2NO3(aq)
In this lab experiment, three milliliters of pure cyclohexane was placed within a test tube and lowered into an ice-water bath. The test tube had a temperature probe within it, which measured the cyclohexane lowering in temperature. Once the cyclohexane solution started to solidify, the cooling curve could be observed and the freezing temperature could be determined. The pure cyclohexane was then thawed, with 0.60 grams of biphenyl being added to the cyclohexane. The experiment was then run again. The result was a freezing point of around 8.6℃ for the pure cyclohexane and 7.0℃ for the cyclohexane-biphenyl solution. To confirm the results that the cyclohexane-biphenyl solution had a lower freezing point, the experiment was ran again. The results
The purpose and goal of this experiment is to use the knowledge of substitution reactions and laboratory techniques to synthesize (2-bromoethyl) benzene from 2-phenylethanol; furthermore, to determination if the synthesis is successful, the methods of thin layer chromatography (TLC), the theorized use of gas chromatography along with a mass spectrometer (GC-MS) and flame ionization detector (GC-FID), as well as infrared (IR) spectroscopy will all have their application in this experiment. The hypothesis of this experiment is that if the synthesis is done correctly and is successful, on the TLC, the expected synthesized (2-bromoethyl) benzene in lane 1 should match that of the standard (2-bromoethyl) benzene in lane 2 but may also contain some impurities, somewhat
I am going to carry out an experiment to measure the change in mass of
The purpose of this lab was to calculate the ratio of moles of water to anhydrous salt by measuring the mass of the water lost and the mass of the remaining anhydrous salt. Ultimately being able to use the ratio to determine the formula of the original hydrated salt. My hypothesis was: If we determine the correct ratio of moles of water to moles of anhydrous salt, then we will find that the water and the anhydrous salt are equal parts in the hydrate because it does not appear to contain a lot of water. This hypothesis was rejected by data.
Determining the Relative Atomic Mass of Lithium An experiment has been carried out to determine the relative atomic mass of Lithium by using two different types of methods The first method that was carried out was to determine the volume of Hydrogen produced. In this experiment a fixed amount of Lithium was used, in my case it was 0.11g. At the end of this experiment, the volume of Hydrogen gas I collected was 185cm³. Then using the solution of lithium hydroxide made from experiment one, I used it in the titrating experiment, to find out the total volume of Hydrochloric acid used to titrate the lithium hydroxide. RESULTS TABLE Experiment Initial Volume ( cm³) Final Volume ( cm³) Total volume Of HCl used ( cm³) Rough 0.2 30.3 30.1 1 6.3 35.8 29.5 2 2.7 32.0 29.3 Average 29.6 CONCLUSION Method 1 [IMAGE]2Li (s) + 2H20(l) LiOH(aq) + H2(g) Number of moles of Hydrogen. Volume of hydrogen gas was 185 cm³. Weight of Lithium was 0.11g. N = __V__ _185_ = 0.0077 MOLES 24000 24000 Number of moles of Lithium.
When 1-bromobutane is reacted with potassium t-butoxide there is only one product formed, 1-butene. This is because the halide is on a primary carbon thus producing only one product.
The objective of this experiment will be to combine various substances, liquids and metals, and to observe their behavior when they are combined. The types of reactions observed shall determine the nature of these reactions: physical or chemical.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
...form 〖PbCrO〗_4 and then process it through a filter. After filtering the 〖PbCrO〗_4 I had to dry the 〖PbCrO〗_4 residue in the drying oven for 30 minutes at 80℃. Then let it cool for 5 minutes and weigh it and finally make a few calculations to obtain the theoretical, actual, and percent yields of 〖PbCrO〗_4. I was able to fulfill the experiment because I obtained all the answers to the equations in an accurate amount. I believe this experiment was a success due to my hypothesis of, If physical methods are used to separate 〖 PbCrO〗_4 precipitate from the reaction mixture then I can successfully calculate the theoretical, actual, and percent yields, being correct.
One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout). It is essentially using the the mass of the product to figure out the original mass that we are looking for. Thus the purpose of our experiment was to compare the final mass in our reaction to the initial mass and determine the change in mass.
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Determining the Activation Energy of the Reaction Between Bromide Ion and Bromate Ion in Acid Solution