home / study / science / chemistry / questions and answers / 1.calculate the amount of na2hpo4�7h2o (in grams) ... Question 1.Calculate the amount of Na2HPO4 x 7H2O (in grams) needed to make 50mL of a 0.40 M solution. 2. Calculate the amounts of Na2HPO2 andNaH2PO4 (in grams) needed to prepare 200 mL of a buffer with pH =8.25 so that the sum of concentrations of (HPO4)2- and (H2PO4)-ions is 0.5 M. pKa1=2.12, pKa2=7.21, pKa2=7.21, pKa3=12.38 3. Writethe equations for the ionization of 3-aminophenol. Would thissubstance be more soluble in water at pH 2.0 or pH 8.0? Would youexpect this substance to be absorbed into the bloodstream in thestomach or the intestines? If you could show your work, that wouldbe most helpful. I am lost at what to do.