B. Using the graph on the next page, plot the measured pH versus the total mmoles of H+added for each addition, and draw the best curve through the points (start plotting at the middle of the graph). C. How many mmoles OH–are in 0.5 mL of a 1 M NaOH solution? D. Plot the measured pH vs. the total mmoles of OH-added after each addition on the same graph (start plotting at the middle of the graph). 0.04.760.54.911.05.061.55.242.05.462.55.803.06.543.57.93mmoles addedpH(0.5 mL of 1M H+)(H+ added)_0.04.760.54.611.04.451.54.282.04.062.53.713.02.993.51.60 4
— — — — — — — — — — — — — — — — — — l l l l l l l l l l l l l l l l l l 0 l H + added (mmol) OH - added (mmol) pH Graph: H+ added 0 / 2 / 4 OH- added 0 / 2 / 4 Answer 0 / 1 / 2 ________pts /10 pts E. The buffer capacityof a solution is defined as the number of moles of H(or OH-) required to change the pH of the solution by one pH unit(for example, the number of moles of acid required to change the pH from 4.76 to 3.76 or the number of moles of base required to change the pH from 4.76 to 5.76). It is a measure of how well a buffer works.From your graph, determine the buffer capacity of the acetic acid/sodium acetate buffer (your answer will be either mmoles of H+ or OH–required to change the pH by exactly 1 pH unit). Perhaps an average of both values would be best. +
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- Spring '13
- pH, buffer solution, mmoles