Blue Bottle Reaction Lab

[see bottom of document for revision suggestions]

By: Sean Aryan, Collin Cardot, ParthSinojia, and Liam White

I. For the initial experiment we saw that when you shook the solution of water, sodium hydroxide, dextrose, and methylene blue it turned a dark shade of blue and changed back to white after around 20 seconds. For the experimental conditions number VIII when the ascorbic acid and copper II sulfate were used and mixed with the methylene blue and shook the solution turned teal and then changed to a little yellow color.[language]. [Also, please use uniform font size]

II. Hypothesis: For the initial experiment our hypothesis was if you add dextrose and sodium hydroxide to water and add 3 drops of methylene blue and shook the erlenmeyer flask, then the solution will stay the color blue and not change. For the experimental condition Vll, if you double the amount of dextrose, then the color will change back to the cloud white color faster after you shake it. For the experimental condition Vlll, if the you use ascorbic acid and copper ll sulfate, then the color will be blue when the drops of methylene blue are added and change to a light yellow color.[language]

III. Experiment: [this section of your lab report should be the PROCEDURE ONLY . What you observed and your qualitative and quantitative data should go in your RESULTS section. ].For the first experiment, we used the following materials: 60 mL of tap water, an Erlenmeyer flask[capacity?], a graduated cylinder[capacity?], a scoopula, scale[digital? Triple beam? And to what precision? Tenths place value? Hundredths place value?], a plastic weigh boat, 2g of dextrose, 1.6g of sodium hydroxide, a rubber stopper, methylene blue, and a dropper. We began the experiment by measuring 60 mL of tap water using a graduated cylinder [capacity?], then transferring it to an erlenmeyer[sp?] flask. Next, we put on safety gloves, an apron, and our goggles to measure the dextrose by placing a plastic weigh boat on the digital scale, setting the scale to 0 and using a scoopula to put the dextrose on the weigh boat. After measuring 2 grams, we added the dextrose to the flask and swirled it in order for it to dissolve, creating a solution. Then, we measured the 1.6g of sodium hydroxide, using the same process as used for the dextrose. Next, we added the sodium hydroxide to the solution and secured the rubber stopper so we could swirl the solution vigorously, eventually dissolving it and creating a homogenous solution.[Why did you need to take extra precautions when measuring NaOH?] After this process, our instructor added one drop of methylene blue, setting off our experiment. We swirled the solution again to create a uniform, blue solution. Afterwards, we began our trials, first we set a timer for 20 seconds and shook the solution vigorously, which resulted with it turning a deep blue color. Then, we let it sit for 30 seconds and recorded the change to a cloudy white color and a formation of a dark blue ring above the solution. Once the 30 seconds passed we repeated the shaking for 20 seconds and observed a transformation back to the deep blue. However, now we let the solution sit for 40 seconds and observed the same changes as before, but at a different rate. After we shook the solution one more time for another 20 seconds, resulting with the same blue color appearing. Finally, we let the solution stand still for 50 seconds, then for 5 minutes. After recording the rate in which the solution changed color, we did the last round of shaking for 20 seconds and observed the final changes. For experiment VI, the process remained the same, except when adding the dextrose, our group measured 4 grams. This resulted with the solution changing to a white cloudy color quicker compared to the original experiment. For experiment VIII, the process remained constant as well, except for the materials used. This experiment required us to measure 75 mL of water compared to the original 60mL, add .6g of ascorbic acid instead of the dextrose. We also added 4 drops of 1M cupric sulfate to the solution. This created a color change for our solution.

IV. Data[Results not data]: For experiment one, we started with a deep, uniform blue. After the first trial that was 20 seconds long, we got about 35 shakes in. The solution started to turn a lighter color after 22 seconds. When the solution turned lighter a dark blue ring appeared at the top of the solution. We repeated the same process for 20 seconds again while this time getting 43 shakes. The solution took 22 seconds to get lighter this time. For the third trial we got 48 shakes in 20 seconds. The solution took 32 seconds to turn lighter this time. It’s worth noting that the solution got a little lighter every time and the ring got a little darker. We let the solution sit for 5 minutes after this. After the first minute, the solution was a little cloudy or translucent. After the second minute the solution’s color started to sink. Then in the third minute it began to get cloudy again. Nothing noticeable happened in the next two minutes. We shook the solution for 20 seconds one last time, this time working in 43 shakes. It’s also worth noting that bubbles appeared after this shake and it was noticeably lighter. The ring was very dark, and it took all 30 seconds for the solution to become lighter.

For experiment 8, we started again with a uniform blue. After the first trial, we got 44 shakes in 20 seconds. The solution took 25 seconds and turned light teal. Another 20 seconds with 43 shakes and we get a light teal, that is almost clear in 15 seconds. Yet again, 20 seconds, 32 shakes yields 17 second wait time to turn light. In 50 seconds the solution turned a light teal. In the first minute of the 5 minute wait, the solution turned yellow, translucent, and foggy. It remained that way for the five minutes. Then when it was shaken up for the last twenty seconds, in 35 shakes, it turned a deep teal and took 25 seconds to get lighter.

For experiment 6 we had 45 shakes in the first 20 seconds, we noticed that it takes less time to turn lighter as it turned light in 7 seconds. This process repeated through the second and third trial with the same amount of shakes and seconds to turn light. After letting it sit for 5 minutes we noticed that the ring looks thinner than in the normal experiment. After the last trial, even though we had the same amount of shakes as last time, it took 10 seconds to clear up.

V. [Hypothesis Analysis]:Our hypothesis was right for the experiment with double the amount of dextrose, but our hypothesis was wrong for the initial experiment and the experiment with copper II sulfate. As we doubled the amount of dextrose used, the time it takes for the solution to turn back to clear from dark deep blue decreased. [Ideas as to why the differences between the experimental variations?]. [Also, why was your hypothesis wrong with the copper II sulfate and ascorbic acid experiment?]

VI. Conclusion: [This section should be a concise summary of both the experiment section (procedure) and the results section (your documented qualitative and quantitative data) as well as some background theory information as to why this phenomenon occurs. See below for more detail. However, I do like that you’ve incorporated your initial hypotheses and your hypotheses analyses. Keep that part!].Our hypothesis was right for the experiment with double the amount of dextrose, but our hypothesis was wrong for the initial experiment and the experiment with copper II sulfate. As the amount of dextrose used increased, the time it takes for the solution to turn back to clear from dark deep blue decreased. This is because dextrose is what causes the solution to change back to the milky-clear color so, if more dextrose is added, it will not take as long for the solution to go milky-clear. Using ascorbic acid and copper II sulfate changed the colors before and after the flask was shaken. The color changed from being a deep blue with the sodium hydroxide to being a quasi-teal color when the flask was shaken. With copper II sulfate, the solution also was a different color after it was left alone. The color went from being milky to being a copperish, yellow color because of the copper.

[For the conclusion section of your report, please conduct some outside research into the chemistry as to why this phenomenon occurred. You should look for terms such as “protonation”, “oxidation”, “reduction”, “reversible reactions”. Explain the scientific theory behind the phenomenon that has been established through rigorous scientific investigation. At this point in the course, you will not fully comprehend the academic language because we haven’t covered this content. However, it is good to include scientific theory and chemical mechanisms here. Also, make sure to CITE YOUR SOURCE as this is new information.]

[In your results section, it is good to have pictures of your actual experiment OR pictures of the blue bottle reaction (which can be easily googled and incorporated into your document). Time lapsed video feed of the phenomenon occurring embedded into your results section is also a plus. Other inclusions to your results section that will help make your report stellar include data tables & data graphs (line graphs or bar graphs are great) showing your quantitative data and how changes occur). Finally, images of molecular structures of the substances used in this lab can help a great deal – which can also be googled. Be sure to cite your source on your images as well (if you google them).]

[In future laboratory reports, please refrain from using first person language and instead, use past tense third person language. IE “we hypothesized that….” Vs “the hypothesis for the occurrence of this phenomenon was…”

[You forgot about your COMMENTARY SECTION and your HONORS/EXTRA CREDIT SECTION]