test:  Ch. 17 equlibrium 3                    110 points                                                        AP 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. A 100.0 mM aqueous solution of sodium carbonate was added to a 125 mL aqueous solution contains 1.0 mM calcium nitrate and 1.0 mM copper (II) nitrate.  [20 points]

a. what is the first precipitate to form ?  justify your answer and explicitly state any assumptions.

b. what is the minimum volume of sodium carbonate to produce the first precipitate to form ?  justify your answer. 


2. In solving acid – base titration problems, a “mice” table is used, where an implicit assumption is that all of the limiting reactant becomes product -  prove / justify / rationalize the validity of this assumption – in the context of titration involving ___.  [hint: recent email & referring to the net ionic equation maybe helpful; 15 points]

a. adding KOH to HNO3

b. adding NaOH to acetic acid

3. Compare the relative solubility of silver chloride in water versus an aqueous solution containing, e.g. potassium chloride (and / or silver nitrate).  Justify / rationale your answer; hint:  common ion effect – reading assignment [10 points]


4. What is the pH after the addition of  ___ to 50.0 mL of 25 mM HCl ?  [20 points]

a. 35 mL of 36 mM KOH

b.  27 mL of 45 mL KOH

 

5. What is the pH after the addition of  ___ to 50.0 mL of 25 mM lactic acid ?  [25 points]

a. 35 mL of 36 mM KOH

b. 27 mL of 45 mL KOH


6. A weak acid (e.g. acetic acid) - strong base (e.g. NaOH) titration curve is shown below.  Assume that there are “eight acetic acid molecules” at V(NaOH) = 0 mL.  Show the relative amount of all species, i.e. molecules / ions, present at V(NaOH) = ___. [20 points]

http://mccord.cm.utexas.edu/courses/spring2012/ch302/image302/titration.png
Source:  http://mccord.cm.utexas.edu/courses/spring2012/ch302/review2S12.php

a. 0 mL

b. 30 mL

c. 60 mL

d. 70 mL