Ch. 15  solution                       test       [50 points]


For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.   


Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.


                                                                                                Signature:  ___________________


  1.  Describe how to prepare a 500.0 mL aqueous solution of 25.0 mM calcium chloride using  ___.  [20 points]

 a. Solid calcium chloride and water


       b.  75.0 mM calcium chloride solution



 2. Excess sodium sulfide was added to a 35.0 mL aqueous solution of silver nitrate, which formed 1.5 g of a precipitate.  Based on the preceding information, determine the concentration of silver nitrate prior to the addition of sodium sulfide.  [10 points]



 3.  In regards to a 25.0 % NaCl solution, what is the  ___ of NaCl ?  Assume the solution’s density is 1.19 g / mL.  [20 points]

 a.  Molarity


b.  Mole fraction