labreport10 - Lab report 10 Assigned Buffer Information...

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Lab report 10 Assigned Buffer Information Table Volume (mL) 100 mL Concentration (M) 0.050 M pH 7.00 Acid and Base information of buffer Table Component Molar Mass (g/mol) Mass (g) mols Na2HPO4 · 7H2O 268.09 g/mol 0.511 g 0.001907 mol NaH2PO4 · H2O 137.98 g/mol 0.433 g 0.003093 mol Result of buffer change and unbuffer change Table Experimental measurement pH DI Water 6.48 Phosphate Buffer 6.71 Buffer + NaOH 6.73 Buffer + HCl 6.60 NaOH in H2O 11.49 HCl in H2O 2.61 Calculated Prediction pH NaOH in H2O 11.52 HCl in H2O 2.56 NaOH in Buffer 7.07 HCl in Buffer 6.93 Claims: My assigned buffer made up of 0.511 g of Na2HPO4 · 7H2O and 0.433g of NaH2PO4 · H2O dissolved in 100 mL of water with measured PH of 6.71. The initial buffer pH was 6.71 and after addition of the NaOH the pH was 6.73. When we added the NaOH to the DI water with initial pH of 6.48 the DI water pH increased significantly and changed the pH to 11.49. The initial buffer pH was 6.71 and after addition of the HCl the pH was 6.60. When we added the HCl to the DI water with initial pH of 6.48 the DI water pH decreased significantly and change the pH to 2.61.

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