Chemistry 112 Buffers - Drew Rasmussen Chemistry 112L...

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Drew RasmussenChemistry 112LPartner: JayKatri TruhlerApril 14, 2011Phosphate Buffers Lab Write-UpA.Research Questions:a.What is the mole ratio required to prepare your assigned buffer (pH 8.00, 0.05M)?b.What was the experimentally measured pH of your buffer?c.What were the calculated pH’s for your Base + Water and Acid + Water?B.Theoretical Approach:a.Using the Hendersen-Hasselbach equation (an equation designed specifically for calculating base pH, mole ratio, and Kavalues) a buffer will be created to match an assigned pH and concentration value. By using this equation you can solve for the required mole ratio of the assigned buffer. With the mole ratio, and the concentration known you can then solve for the amount of acid and base (in grams) required to prepare your buffer. Once the solution has been mixed up using the calculated weights of acid and base, it is possible to test how the buffer reacts to the addition of acid or base, and how this compares to adding an acid or base to pure water.C.Observations and Results:a.The Base is a white powder that tends to clump together. No apparent smell.b.The Acid is a white crystalline solid about the 5 or 6 sugar granules. No smell.
c.The NaOH and HCl used were both 0.1M. Found in white bottles on top of work station shelf.d.The masses were carefully weighed out to within + or – 0.001g of the calculated weight and put in a 100mL volumetric flask. They dissolved fairly easily with some shaking. The buffer solution is clear. No apparent smell.

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