Name:  ______________________________                                                date:  _______

 

Ch. 5, 8.9, 11.4, 19, & 24.1   thermodynamics & complex ion           test     [90 points]                   AP Chem

 

For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.  Clearly identify the problems done and do them in sequence and your answer must begin and end on the same page of paper; otherwise, you will lose points.  attach this sheet to the front of your exam.

 

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:  ___________________

 

1.  Using thermodynamics, determine / justify if the following reactions are spontaneous at 25 °C:  [10 points]

 

a.  the decomposition of diamond (into graphite)

 

b.  the decomposition liquid hydrogen peroxide (into water & oxygen gas)

 

2.  What is the maximum grams of ice (i.e. solid H2O) at 0 °C that could be melted (to form liquid water at 0 °C) by the completion combustion of 1.0 grams of butane (into its gaseous products)  [15 points]

 

3.  Compare the thermodynamics of dissolving solid sodium hydroxide versus solid potassium hydroxide in water at 25 °C.  [15 points]

 

a.  calculate ΔS for each process

 

b.  what is / are the implication(s) of the difference in the relative value of ΔS for each process; refer / define the term, hydration shell, in your response.

 

4.  Determine the bond enthalpy of O2 based on the following information 

 

Bond enthalpy  (kJ / mole)

 

C – H     413

C – C      348

C = C      614

C – O      358

C = O      799

O – H     463

 

The complete combustion of 1.0 mole ethane generates 1416 kJ  [15 points]

 

5.  In regards to the determination of the heat of fusion of water,   [15 points]

 

a.  list the experimental measurements, not calculations, needed

 

b. describe its data analysis; include all relevant equations / formulas & the proper sequence of using these equations

 

6.  Based on the following information,

 

                Fe2O3  +  3 CO  à  2 Fe  +  3 CO2                     ΔH1 = - 23 kJ

                3 Fe2O3  +  CO  à  2 Fe3O4  +  CO2   ΔH2 = - 39 kJ

                Fe3O4  +  CO  à  3 FeO  +  CO2                         ΔH3 = 18 kJ

 

determine the change in enthalpy for the reaction   [20 points]

 

                FeO  +  CO  à  Fe  +  CO2