Ch. 7 & 14  chemical equations & IMF                       test     [55 points]                   honors Chem

 

 

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. Balance the following chemical equations using the lowest ratio of integers; enter “1” as appropriate.  [18 points]

a.   ___  C2H6  +  ___  O2  à  ___  CO2  +  ___ H2O

b.  ___  K2CO3  +  ___  Mg(NO3)2  à  ___  KNO3  +  ___  MgCO3 

c.  ___  Fe  +  ___  O2  à  ___  Fe2O3

d.  ___ KClO3  à  ___ KCl  +  ___  O2

e. ___ Aluminum bromide  + ___ potassium sulfate à  ___ potassium bromide + ___ aluminum sulfate


2. In regards to (clearly identify the compound – alcohol or ether – in your answer)  [25 points]

 

       H   H                                       H           H

        |     |      . .                                 |     . .     | 

H – C – C – O – H    versus    H – C – O – C - H

        |      |     . .                                 |     . .     |

       H    H                                      H           H

 

    (alcohol)                                          (ether)

a.  is it a polar or nonppolar compound ?  justify your answer.

b. Identify the IMF in the compound

c.  What is the relative IMF between these compounds ?

 

3. Sketch / label a vapor pressure versus temperature graph with 2 curves.  Which curve corresponds to the alcohol versus ether ?  justify your answer.


4.
In regards to your chromatography lab to separate the red and blue dyes, rationalize the following observations using concepts involving IMF.   [10 points]                   

structure of dyes, rubbing alcohol, & stationary phase shown in test, not here

a.  Water was unable to eluate any of the dyes.

b.  70% alcohol eluated both of the dyes, together.

5. In regards to a molecule, what is the relationship between the dipole moment and bond dipole ?  [2 points]