CHEM  1A                  EXAM IIA

1.  (10)  Write the net ionic equation for the reaction that occurs, when the following reagents are combined in an aqueous solution.  If there is no reaction, write N.R.

            (a)   Ba(OH)₂   +     HNO₃  =

            (b)   Fe(OH)₂    +     HCl     =

            (c)  K₂SO₃   +     HI   =

            (d)  (NH₄)₂CO₃     +       BiCl₃      =

2.  (6)  Complete and balance.  Name the type of reaction.                                                          Type of reaction

            (a)      Mg    +      S₄   =                                                                               _________________________

            (b)      SnBr₂  +   Al     =                                                                              __________________________

3.  (9)  How many grams of AlCl₃ (s) must be added to 45.0 mL of 0.200 M CaCl₂ to prepare a solution that has

            [Cl^–] = 3.50M ?  (assume the volume does not change)

4.  (5)  What is the mass ( in grams) of CaBr₂ needed to prepare 85.0 ml of a 1.35 M aqueous solution of CaBr₂ ?

5.      (10)  Balance in acidic solution:                  

                                    Pb    +     ClO₃^–           =     Cl^–        +      Pb⁴⁺ 

oxidant______________  

reductant_____________

6.   (10)  Balance in basic solution:

                                    As₂S₃      +      NO₃^–     =    HAsO₄^2–   +   SO₄^2–   +    NO 

oxidant______________  

reductant_____________

7.  (6)   2.445 g  of an unknown acid were titrated with 25.5 mL of a 0.175 M solution of Ba(OH)₂.  What is the equivalent             weight of the unknown acid.

8.  (18)  7.8200 g of a mixture of SbCl₃ and Fe₂O₃ were reacted with excess Na₂S to produce 8.0750 g of a mixture of       FeS and Sb₂S₃.  What is the %of SbCl₃ in the original mixture?  (hint:  balance only the Fe and Sb – the reaction to      produce FeS is a redox reaction which also produces elemental S.)

9.  (8)  35.00 mL of an H₃PO₄ solution were used to titrate 28.75 mL of a 0.665 M solution of  KOH.  What is the molarity of             the acid solution?  What is the normality of the acid solution?

10.  (13)  375 g of PCl₅ were reacted with excess Cl₂, and excess P₄O₁₀ in the following consecutive reactions.

            Reaction 1:

                        2 PCl₅     +    Cl₂    =    P₂Cl₁₂   

            Reaction 2:

                        7 Cl₂   +   3 P₂Cl₁₂   +   P₄O₁₀   =   10 POCl₅   

            If 285 g of POCl₅ are measured for the final product, what is the overall % yield for the reactions?

            If the second reaction has a 17.0% yield, what is the % yield for the first reaction?

11.  (5)  45.0 mL of 2.88 M Na₃PO₄ solution was diluted to a final volume of 1.750 L.  What is [Na⁺] in the final solution?