Using the square-bracket notation, express the concentrations of ions in a solution that is 0.750 M in aluminum sulfate [Al2(SO4)3].

Calculate the equilibrium concentration (in M) of PO43− that would be present in a mixture that is originally 0.015 M H3PO4 as well as 0.005 M NaH2PO4, given the following information:     H3PO4(aq)   ↔   H+(aq)   +   H2PO4−(aq)                   Ka1  =  1.5 x 10−5   H2PO4−(aq)   ↔   H+(aq)   +   HPO42−(aq)                 Ka2  =  2.5 x 10−7   HPO42−(aq)   ↔   H+(aq)   +   PO43−(aq)                    Ka3  =  3.5 x 10−9

4. A solution prepared to be initially 1 M in NH3 and 0.5 M in HCl is (Kb for NH3 = 1.8 x 10¯5):   (A) a solution with a pH less than 7 that is not a buffer solution  (B) a buffer solution with a pH between 4 and 7  (C) a buffer solution with a pH between 7 and 10  (D) a solution with a pH greater than 7 that is not a buffer solution  (E) a solution with a pH of 7

2. Using the procedure described in this module, a student determined the percent KHP in an impure sample of KHP. A 3.150-g sample of impure KHP required 41.50 mL of 0.1352M NaOH solution for titration. (a) Calculate the number of moles of NaOH required for the titration. (b) Calculate the number of moles of KHP present in the impure sample of KHP. (c) Calculate the number of grams of KHP present in the impure sample. (d) Calculate the percent of KHP in the impure sample, using Equation 8. Equation 8: percent KHP in the impure sample, % = ( mass of KHP in the sample,g/ mass of sample analyzed, g) (100%)