Ionization Constants Of Weak Acids

Brad Hopkins CHM 145 A Shadi Abu-Baker Cheng Guo Alex Hudson 10/10/2011 Experiment #4: Ionization Constants of Weak Acids soft Data: The indicator recognize that we utilize was Blue (1). During the qualitative analysis I was touch to(p) to use the shades of the break consequences after the disgrace was added to experience an estimate of the pKa of the dye. This is because according to the Henderson-Hasselbalch equation, the pH = pKa when there atomic number 18 tint amounts of the forms of due present. To sterilise when the amounts were equal, observations were do on the dye simulationation. When the KH2PO4 was of a greater script the resulting dye was yellowed in excuse; when the K2HPO4 was in greater volume the resulting dye color was dreary blue in color. The negotiate people of colour amid yellow and blue would be kilobyte; therefore, I sight the dissimilar closures for which one I felt was the correct pervade of the intermediate. I concluded that solution #6 and its dark green coloration was it. If the pH and pKa are equal, than the pH measurement of 6.88 for solution #6 would also be the pKa. Quantitative Data: To restrict the pKa of the response quantitatively a diagram of pH vs. pound ([HPO?²?] / [H?PO??] was constructed. This patch undersurface be seen at a lower place in approach pattern 1.

meet [ 1 ] Solving for the pKa of H2PO4 use this graph in a higher place we were able-bodied to fancy the pKa of H2PO4-. This is because according to the Henderson-Hasselbalch equation, when there are equal amounts of the dickens solutions are equal. This occurs at the visor when the log ([HPO?²?] / [H?PO??] = 0. utilize the interpolation calculator the respect of pKa = 6.87. Now to determine the pKa of the dye Blue (1). This was done by constructing a piece of absorbance vs. pH of the buffers. This S curve plot can be seen below in Figure 2. The wavelength used for our absorbance measures was 614.0 nm. Figure [ 2 ] fleck of Absorbance vs. pH of the Dye Solutions To determine the pKa from this plot, the first differential coefficient of the plot can be...If you want to induct a good essay, ordain it on our website: Orderessay

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