Crystal Violet Dye Formal Lab Report

Photograph Description: Photograph 1, shown on the previous page, was taken after 20 drops of the crystal violet dye was added to the solution, and photograph 2 was taken after 40 drops were added. As seen in the pictures, only a faint ring of violet was visible around the coacervates. Photographs 3-5 were taken after adding a drop of 20% concentration crystal violet dye onto the side of a slide.

Discussion
The initial experiment had results that were slightly different than I had predicted. In my hypothesis, I stated that coacervates would start forming when the pH was 5, but be most abundant when the pH was 4.5. Prior to the experiment, I did not think the coacervates would change in size, instead, I thought that as the solution

I was correct that coacervates would start forming at a pH of 5, but I found that coacervates were most abundant after this first drop of hydrochloric acid when the pH was 5, instead of a pH of 4.5. The coacervates I observed on the slide were small, and flowed through the field of view. The solution in the test tube was slightly cloudy, but there were no visible precipitates. I was surprised at the size of the initial coacervates, because they were much smaller than I expected, and many of them were clumped together in groups. Once I added the second drop of hydrochloric acid, the solution became even more cloudy. The coacervates that I observed were significantly larger than on the previous slide. However, there were fewer coacervates, and they were not as clumped together as before. After adding the third drop of hydrochloric acid, the solution appeared less cloudy, and there was a visible precipitate at the bottom of the test tube. The coacervates were much fewer in number, and it appeared that some were

Along with that, my pH measurements could have been slightly off, because it was hard to determine the value when comparing the pH paper to the key. In the lab extension, possible sources of error could have come from the concentration of the crystal violet dye solution. If I had not added the drop of 20% concentration dye, I am not sure how many drops it would have taken to see that the membrane of coacervates is permeable to crystal violet dye. If other people perform this experiment, I would recommend using a higher concentration of dye from the start, so that it would not take so many drops to get the results. Until I added the final drop of crystal violet dye, I thought that my prediction was wrong, and coacervates did not have permeability to the dye. After doing some research, I found that other people who have performed this experiment found that the pH when coacervates are most abundant ranges from 4.5 to 5. This confirms my results, and shows me that coacervates are formed in an acidic solution, but break down if the conditions become too acidic. If the Oparin-Haldane hypothesis is correct, then the pH of this primordial sea could have had a pH around 4.5 or