CHM 1046                           TEST  1          Name _______________________
September 20, 1996                              (please print)                  
                                                   Soc.Sec.Num. ________________

      This exam consists of four pages.  Make sure you
have one of each.  Print your name at the top of each
page now.  A fifth page contains a periodic chart and
other information you may need.  You may tear this
sheet off and use it for scratch paper.  Show your
work on calculations, be sure to include units in the
calculations, and give answers to the correct number
of significant figures.  You may use atomic weight
values rounded to the nearest 0.1 amu.

      If anything confuses you or is not clear, raise
your hand and ask!

Points

1.    For the potential reactants below:
      1)   provide the correct formulas in molecular form for the
           potential reactants;
      2)   provide correct formulas for the potential metathesis products
           in the molecular form;
      3)   write a balanced, net ionic equation, or indicate "no net
           ionic equation" if there is none;
      4)   if there is a net reaction, state your conclusion as to
           whether it goes forward, backward, or is indeterminate.


(7)A. aluminum sulfate  +  calcium nitrate











(7)B. iron (III) sulfide  +   barium chloride











(6)2. Circle the strong bases in the following list:

      NH3       Ba(OH)2    LiOH       Ca(OH)2   H2SO4      PbI2



(12)3.Balance the following redox reaction under acid conditions.  Show
      your work by writing and balancing the half-reactions.  Reduce the
      balanced equation by canceling species on both sides and by
      reducing the coefficients to the lowest whole numbers.  Identify
      the reacting species called for immediately below the equation.

      CrO42-   +   H2S   ---->    Cr3+    +    So

      Oxidizing agent ________        Reducing agent ______
















(4)4. Although Al(OH)3 is insoluble in water, it still reacts with an
      aqueous solution of HCl.  What provides the driving force for this
      reaction?  Write the net ionic reaction.









(7)5. You have an aqueous solution labeled 15.7% Pb(NO3)2.  One hundred
      grams of this solution would contain how many moles of Pb(NO3)2?





6.    Urea is a non-electrolyte with a molecular weight of 60.0 g/mol. 
      You dissolve 16 g of urea in 39 g of water, and find the density of
      the solution is 1.3 g/mL.

(7)   (a)  What is the molarity (M) of urea in this solution?











(7)   (b)  What is the molality (m) of urea in this solution?












(3)7. Analysis of your water supply showed it to contain 45 ppb
      manganese.  How many grams of manganese would you consume by
      drinking 325 mL of the water?









(8)8. The vapor pressure of water at 25 oC is 23.76 torr.  What would be
      the vapor pressure of a 15% solution of table sugar (sucrose,
      C12H22O11) in water?
      
      
      
      
      
      
      
      
      
      



(14)9.The freezing point of benzene is 5.5 oC, and the freezing point
      depression constant (Kf) for benzene is 5.12 oC/m.  A solution of
      6.53 g of an unknown substance dissolved in 125 g benzene freezes
      at 1.2 oC.  What is the molecular weight of the unknown, assuming
      it does not dissociate in solution?


















(6)10.In the following list, place an h next to the solution with the
      highest boiling point, and an l next to the one with the lowest
      boiling point.

      ____ 0.15 m acetic acid

      ____ 0.12 m sugar

      ____ 0.07 m barium chloride



(12)11.What would be the osmotic pressure of a 2.5 % sodium chloride
      solution at 25 oC?  (R = 0.08205 L-atm/mol-K)  Density of the
      solution is 1.01 g/mL.