CHM 2045C    Module Five Sample Exam

Module Four-Part K Excess-Limiting Reagent Problem         4 points

 

How many grams of Calcium phosphate can be made according to the reaction(unbalanced):

 

   CaCl2       +     K3PO4     ---->        Ca3(PO4)2        +   KCl

 

by mixing a solution of 5.00 grams of CaCl2   with another containing 8.00 grams of Potassium phosphate?

 

 

 

 

 

 

 

 

 

 

 

 

Module Four-Part L   Impure Reagents/% Yield Stoichiometry Problem 4 points

 

A laboratory manual calls for 13.0 grams of butanol,  21.6 grams of sodium bromide, and 33.8 grams of sulfuric acid as reactants in this reaction:

 

C4H9OH   +   NaBr     +     H2SO4   ------>     C4H9Br   +   NaHSO4    +   H2O

 

A student following these directions obtains 16.8 grams of butyl bromide (C4H9Br).   What are the theoretical yield and percent yield of this reaction?