Name:  __________________________                                            date:  ________

 

Ch. 4 & 13,  solution test        [75 points]                                           AP Chemistry

 

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:  ___________________

 

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

 

1.  Describe how to prepare the following solutions; show relevant calculations.  [10 points]

 

a.  325 mL 25 mM calcium chloride

 

b.  325 mL 25 mM calcium chloride using a 135 mM calcium chloride solution.

3. A solution of 80.5 g of vitamin C (C6H8O6) in 210. g of water has a density of 1.22 g / mL. Calculate ___ of vitamin C in the solution. [ch. 13.21 problem; 20 points]

a. mass percent                        b. mole fraction

c. molality                               d. molarity

3.  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.  mix solutions of lithium hydroxide and magnesium chloride

 

4.  What is chemical basis of decompression sickness, i.e. “bends” ?  [10 points]

 

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 chemical formula of the fatty acid ?