Irresistible Lab Report Chem 109 Essay

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A buffer is a solution that resists changes in pH when H+, OH-, or H20 is added. By using standard lab equipment, a lab pro diagnostic tool, and acidic and basic solutions, the pH can be found. By recording the pH while adding a base or an acid gradually to a buffer solution you can find the capacity of each buffer to resist drastic changes in pH. The best buffers will keep a solution from becoming either too acidic or basic with the addition of a strong base or acid.
The objective of the Irresistible lab is to determine the capacity of each solution (unbuffered and buffered both) and how much they resist changes to pH. This is accomplished by having ten graduated beakers: two containing pure water, two with .1 M
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It took one mL to reach a significant rise in pH. The other three solutions all took a total of 4 mL to rise to a pH of a little over 13.06.
The Effect of Base on Solutions Trial 50 ml H20 50 mL .1 M NaCl 1 g CH3COONa 5 g CH3COONa 10 g CH3COONa
0 6.77 7.3 4.84 5.625 5.934
1 12.99 13.13 5 5.783 6.164
2 5.36 6.145 6.444
3 6.26 7.955 7.53
4 13.06 13.14 13.14

The point of this lab was to determine the capacity of each solution as a buffer. By adding a strong acid to the solution we were essentially measuring the amount of hydrogen atoms that could be absorbed by the solution (buffered) before the limit was reached and they were abundant in the solution (pH). The same was measured by lack of the hydrogen atoms and abundance of hydroxide ions in solution when the base was added. As seen in the graph above, water has little to no buffering capacity. Because it contains a hydrogen and hydroxide ion, it should have some buffering capabilities, but I suspect that the fact that the acid was strong quickly overcame the capacity. Similar results with the sodium chloride show that it’s buffering capacity is not good. The 1 gram of sodium acetate reached its capacity at 8 mL of HCl, and the other two never dropped off. This shows that they were continuing to buffer past the 10 mL of HCl. The graph above shows the same solutions with the addition of Sodium