Date Performed: June 22, 2012
Univ Irgil Silva
Date Due: June 29, 2012
Date Submitted: June 29, 2012
Experiment No. 1
Preparing Buffers and Buffer Capacity
The principal objective of the experiment1, Preparing Buffers and Buffer Capacity, is to prepare buffer solutions in different concentrations and to determine their buffering capacity. Each group was assigned to certain concentration 0.1M, 0.2M, 0.3M, 0.4M and 0.5M of the acetate buffer to be prepared using acetic acid and sodium acetate. The pH of the prepared buffer was noted and it was titrated by NaOH until its initial pH increases by one unit. The buffer that was prepared was in acidic solution. The calculated buffer capacity of 0.1M, 0.2M, 0.3M, 0.4M and 0.5M concentrations are 0.03003, 0.05340, 0.08294, 0.09824, and 0.1458 respectively. The result revealed that the buffering capacity is higher when the concentration of the buffer is higher and the result corresponds to the theoretical result.
Discussion of Data and Results
Buffer capacity is a quantitative measure of the resistance of a buffer solution to pH change on addition of hydroxide ions. Buffers regulate the pH of fluids and tissues of living organisms within the limits consistent with life and normal functions. It is also used in laboratories in controlling the pH of the culture media for microorganisms and tissues, and is used in many processes such as fermentation, electroplating, and dyes.
Buffered solutions resist the changes in [H¬+] that would otherwise result from the addition of an acid or a base. Buffer action is exhibited by ions of weak acids or bases. Strong acids and bases are almost completely dissociated in water and have no reservoir of undissociated acid or base. Weak electrolytes that exhibit buffer action have extremely important properties and have great value for living systems since most cells can survive only within fairly narrow pH limits.
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