Chemistry Lab Essays (358 words) - Fin, Heat Transfer,

Chemistry May 13, 2015 4A Purpose: The purpose of this lab was to find the concentration of the acid. Adding small amounts of the base helped to do this. You could determine the pH every time and watch it rise until it hit 7. Data and Calculations: The formula MaVa=MbVb helps to determine the concentration of the solution. Initial acid amount: 19.2 mL Molarity of NaOH: .10 M (Ma)(0.0192L)=(0.10M)(Vb) Vb is what needs to be solved (in mL). Diving the number by 1000 will change it to Liters. This number represents the amount of NaOH added. Ma represents the concentration and can be solved for after the Vb is calculated. (Ma)(0.0192L)=(0.10M)(0.2958L) (Ma)(0.0192L)= (0.0296L) ---------------- ----------------------- (0.0192L) (0.0192L) Ma= 1.54 M The Molarity of HCl is 1.54 M. Data Table Buret ReadingmL of NaOH addedpHSolution Color 50.2 mL0.0 mL2Colorless 52.6 mL2.0 mL3Colorless 54.6 mL4.0 mL4Colorless 56.6 mL6.0 mL4Colorless 58.6 mL8.0 mL4Colorless 59.6 mL9.0 mL4Colorless 60.8 mL10.2 mL4Colorless 61.8 mL11.2 mL4Colorless 63.0 mL12.4 mL4Colorless 64.0 mL13.4 mL4Colorless 65.0 mL14.4 mL4Colorless 65.2 mL15.6 mL4Colorless 67.2 mL16.6 mL5Colorless 72.0 mL19.4 mL5Colorless 74.0 mL21.4 mL5Colorless 75.0 mL22.4 mL5Light Pink 77.0 mL24.4 mL9Pink 79.0 mL26.4 mL12Pink 81.0 mL28.4 mL12Pink 83.2 mL30.6 mL12Magenta Conclusion: The goal of this lab was to determine the molarity of HCl. We solved to find the Vb for the equation, MaVa=MbVb. Va and Mb were already given to us so the last step was to solve for the Ma. We started out with 19.2mL of HCl. From there we added 3-4 drops of phenolphthalein, which served as an indicator to tell when we would hit a pH of 7. Gradually, we added 2mL of the base, NaOH. The total amount of mL of NaOH that we added was roughly 296 mL. The equivalence point is 22.4 mL, which is the same amount of mL that turned the liquid pink and had a pH of 7.