0.100m Tris Lab

During the preparation of the 0.100M Tris buffer, the calculated amount of ingredients brought the solution to a pH of 7.0, but the desired pH was 7.50. Discrepancies between the theoretically calculated amounts and the actual measured amounts of ingredients are likely to be the biggest source of error. Dilution affected our 0.0100M Tris buffer by decreasing its pH. The buffer was originally set to a pH of 7.48, but the pH gradually moved down by a pH unit of about 0.1 after each dilution. This is agrees very well with what we expected prior to lab because the reading discussed how Tris buffers are affected by the concentrations. It even stated that it can be expected to change by 0.1 pH units for every tenfold dilution, so our buffer seemed to agree quite well with the literature.
This was even better than our predicted pH of 7.93 based on our calculation, and this difference could be due to error in the calibration of our pH meter, error when measuring amounts of components, or problems with the pH meter, as we were struggling with it throughout the lab because it kept resetting itself back to a pH of 7.0. To compare the effectiveness of the buffer, 0.5 mL of NaOH was also added to a 30 mL solution of water. The water experienced a much greater increase in pH than did the buffer as it jumped from a pH of 6.66 to 11.62. This difference was actually smaller than our calculated value, 12.2, but this could be due to similar errors as mentioned before. This difference in pH change demonstrates how effective buffers are at maintaining pH compared to plain water, and shows that Tris is a relatively good buffer at this