Ch. 4, 13, & 24 solution & complex ions [80 points] AP Chemistry

For problems involving calculations, show your work in an organized manner, include any relevant formula / equation, the proper units in your work and answer, and the proper number of significant figures in your answer. Water is the solvent in all solutions unless otherwise stated.

 

1. Give the formulas to show the reactants and products for the following chemical reactions. Each occurs in aqueous solution unless otherwise indicated. Represent substances in solution as ions if the substance is extensively ionized. Omit formulas for any ions or molecules that are unchanged by the reaction. In all cases a reaction occurs. You need not balance (the coefficients in the reactions) [15 points]

a. potassium metal added to water

b. tetraphosphorus deca-oxide in water

c. mix solutions of barium nitrate and sodium sulfate

d. mix solutions of sodium bicarbonate and acetic acid (or hydrogen acetate)

e. add concentrated ammonia to a solution of zinc chloride

 

2. Describe the preparation of the following solutions. [20 points]

a. 250. mL of 25 mM magnesium hydroxide

b. 250. mL of 25 mM magnesium hydroxide using a 150. mM solution of magnesium hydroxide

 

3. An aqueous solution of 0.9 % NaCl (by mass) has a density of 1.009 g / mL. [15 points]

a. determine the molarity of NaCl in this solution

b. determine the osmotic pressure of the solution at 25 °C

c. define the term, osmotic pressure

 

4. Describe an experimental method and its anticipated results to differentiate a solution of copper (II) nitrate from other potential solutions: [10 points]

BaCl2           CuCl2                 Na2CO3

Ba(OH)2       Cu(NO3)2         NaI

                      CuSO4             NaOH

                                               Na2SO4

 

5. The boiling point of chloroform, CHCl3, is 61.2 °C, its Kb = 3.63 °C /m and Kf = 4.68 °C / m. A fatty acid contains 72.0% carbon, 12.0% hydrogen, and 16.0% oxygen. A solution containing 1.5 grams of the fatty acid dissolved in 10.0 grams of chloroform has a boiling point of 63.92 °C. [20 points]

a. what is the molality of the fatty acid in solution ?

b. what is the molar mass of the fatty acid ?

c. what is the empirical formula of the fatty acid ?

d. what is the chemical formula of the fatty acid ?