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E-mail me the answer to the following questions.  If the question is a calculation, send the answer and a description of how you arrived at the answer (you need not try to type in math).  See the Instructions for Problem Sets. (Use the "Back" button or menu command on your browser to return to this page.) 

1.  Answer Question 5 on the 1995 AP examination. (An example of an AP essay question.) 

2.  Answer Question 2 on the 1993 AP examination. (An example of an AP  free response problem.) 

3.  Explain why the molar enthalpies of vaporization of the following liquids increase in the order 

CH₄ < C₂H₆ < C₃H₈

4. The melting point of H₂O(s) is 0^oC. Should you expect the melting point of H₂S(s) to be -85, 0, or 185^oC? Explain your answer.  (This doesn't look loke a solutions based question, but it does deal with intermolecular forces.) 

5. The types of intermolecular forces in a substance are identical whether it is a solid, a liquid, or a gas. Why, then does a substance change phase from a gas to a liquid or to a solid?

6.  A.  Indicate the most important type of attraction between the solvent and solute in each of the following solutions: 

(a)  Ammonium chloride in water. 
(b)  Methanol, CH₃OH, in ethanol, CH₃CH₂OH 
(c)  Methane, CH₄, in benzene, C₆H₆
(d)  O₂(l) in N₂(l)

7.  (a) Outline the steps necessary to answer the following question: What is the boiling point of a solution of 9.04 g  of  I₂ in 75.5 g of benzene, assuming the I₂ is nonvolatile?   (b) Answer the question. 

8.  (a) Outline the steps necessary to answer the following question: Using a poorly calibrated thermometer, a student in a laboratory experiment measured the freezing point of a sample of water as 0.12^oC  What is the freezing temperature measured with the same thermometer of a solution of 115.0 g of sucrose, C₁₂H₂₂O₁₁, in 350.0 g of water?        (b) Answer the question. 

9.  A sugar contains 40.0% C,  6.7% H, and 53.3% O by mass.  A solution of 11.7 g of this sugar in 325 g of ethanol has a boiling point of 78.59^oC.  The boiling point of ethanol is 78.35 ^oC, and K_b for ethanol is 1.20 ^oC/m.  What is the molecular formula of the sugar?