Chem 106 Lab 13 - Lab Report#13 Drop some Acid Drop some...

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Lab Report #13 “Drop some Acid, Drop some Base” Introduction:One of the most important concepts in the study of acid-base chemistry is the buffer. A buffer is a type of aqueous solution which has a very stable pH. This means that the buffer will, for a time, resist a change in the pH due to the addition of a certain amount of strong acid or strong base. Buffer solutions usually consist of a weak acid and its conjugate base, in relatively equal and large concentrations. This ensures that the buffer remains in equilibrium, allowing the equilibrium to move either backwards or forwards to minimalize any changes to the pH of the solution. In a non-buffered solution, such as distilled water, if we were to add a strong acid or strong base, the pH of the solution would change drastically, due to the fact that there are no other species in the solution for the acid/base to interact with. However, if a weak acid (HA) in mixed with its conjugate base (A-) in solution, both species remain in solution and will not react with water. However, when these species are mixed in with strong acids or bases they will react, resulting is a very small or even inexistent change in pH. In this lab we looked at an online simulation that showed us both the necessary components needed to make a buffer, as well as the effects that the addition of HCl and NaOH (very strong acids/bases) has on the solutions pH. In part 1 of the lab, we made buffers using varying concentrations of lactic acid and its conjugate base, sodium acetate. Next, we added a setamount (0.050 moles) of both HCl and NaOH to each of these buffers. Now, we must observe to what magnitude the pH of the solution shifted. The solution which shifts the least would be considered the best buffer.Materials:Lab ManualLab NotebookPen or PencilComputer with internet accessCalculatorFocus Questions:1.How does a buffer solution resist a change in pH?

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