A) You need to prepare 300 mL of a 0.5 M phosphate buffer at pH = 6.8 using solid Na2HPO4 and 1.0 M HCl. How many grams of solid Na2HPO4 are required and how many milliliters of 1.0 M HCl? The M.W of Na2HPO4 is 141.96 g/mol and the pKa of H2PO4- is 7.2.
B) Consider the following peptide: Asp-Ala-Lys-Arg-Gln-Met The amino terminal amino acid is: A- Asp B- Met C- Lys D- Arg
C) Consider the following peptide: Asp-Ala-Lys-Arg-Gln-Met The overall, net ionic charge on the peptide at pH 7 would be: A- -2 B- -1 C- 0 D- +1 E- +2