Ch. 15 solution                        test                  90 points                                                                      honors chem

Show your work in an organized manner, including equation / formula, proper conversion factor(s), equation or formula, and units in your work / answer and the proper number of significant figures in your answer.

1.  Describe how to prepare 125 mL of 275 mM sodium hydroxide using solid sodium hydroxide and water; justify your answer.  [15 points]

2. Describe how to prepare 125 mL of 275 mM potassium hydroxide using a 500.0 mM potassium hydroxide solution and water; justify your answer.  [15 points]

3. The addition of excess sodium carbonate, Na2CO3, to a 75 mL aqueous solution of iron (III) chloride, FeCl3, produces 1.0 grams of a precipitate.  What is the concentration of iron (III) chloride prior to the addition of sodium carbonate ?  [15 points]


4. What is the molarity of ____.  [20 points]

a.  Isotonic solution of glucose – it’s 5.0 % glucose, C6H12O6; assume the density of the solution is 1.01 g / mL

b.  125 mL aqueous solution containing 2.5 grams of sodium carbonate

 

5. Does urea, (NH2)2CO, dissolve in water ?  justify / rationalize your answer based on concepts taught in class in regards to the “solution process”.  The chemical structure of urea is shown below. 

http://upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Harnstoff.svg/150px-Harnstoff.svg.png

Urea has an important role in the formation of urine by the kidneys.  The dipole moment of urea is not equal to zero.  [10 points]

6. define __  [15 points]

a. equivalence point 

b. end point