CHEM125-C                                                                                                  Fall, 2005

Hourly Exam # 3                                                                                             Dunnivant

 

Name (PRINTED) ____________________________________

 

There are 100 points.

 

The honor statement must be signed in order for your exam to be graded.

Closed book, closed Internet, closed notes, closed neighbor!

I have neither given nor received aid on this exam.  

                                                            Signature ________________________

 

NOTES:

-Show all work for partial credit.  

-Significant figures and units will be graded throughout the exam.

 

h = 6.63 x 10-34 J¥s

Avg.Õs # = 6.022 x 1023 anythings/mol

c = 2.998 x 108 m/s

R = 1.097x107 m-1

 

  1. Essay question.  Finish the rest of the exam, turn it in, and type your answer to this question in the computer lab!  Strict one-page, single-spaced, 12 point font limit!

 

(15pts)  Contrast the Mendeleev and Schrodinger approach to the organization to the periodic table.  What are the differences?  How are they actually the same design criteria (what is common between each design with respect to the layout of the periodic table)?


  1. a)  (15 pts)  List the seven forms of electromagnetic radiation in increasing order of energy.  Label which end (top or bottom) has the highest frequency.  Label which end (top or bottom) has the highest wavelength.

 

ENERGY                    WAVELENGTH

___________________                high or low                  high or low

 

___________________

 

___________________

 

___________________

 

___________________

 

___________________

 

___________________                high or low                  high or low

 

 

  1.  (10 pts) A photon has a wavelength of 1000. nm.  What is the energy level contained in 1.00 moles of the photons?

 


  1. (10 pts)  An electron in hydrogen goes from a principle energy level of 1 to 4.  What is the energy value of the transition in kJ/mol?

Is the transition endo- or exo-thermic?


  1. (3 pts) Give the complete spectroscopic notation for cadmium.

 

 

 

(2 pt) Give the Noble gas notation for cadmium.

 

 

  1. (10 pts)  Using the Periodic Table below, in general, put

 

a Ò1Ó where the atomic size in the largest

 

a Ò2Ó where the ionic size for cations is the smallest

 

a Ò3Ó where the effective nuclear force is the greatest

 

a Ò4Ó where the electronegativity is the greatest

 

a Ò5Ó where the electron ionization energy is the largest

 

 

 

 

  1. (15 pts)  Draw the Lewis dot structure for CH3CH2CHCHCOCH3  (Cs are the central atoms).  Label the type of hybridization on each carbon (i.e., sp, sp2, sp3, etc.)

 

 

  1.  (15 pts) Draw the Lewis dot structure for N2O (laughing gas, one of the Ns is the central atom), all three possible resonance structures, and using the formal charge calculation determine which resonance structure is the most likely. 

What will actually happen in nature with respect to the correct resonance structure?

 

 

  1. (10 pts) Using average bond enthalpy values, predict if the following reaction will be exothermic:

 

 

CO(g)  +  F2    CF4(g)  +  OF2(g)

 

Bond enthalpy values:             C-O = 358 kJ/mol

                                                      F-F = 155 kJ/mol

                                                      C-F = 485 kJ/mol

                                                      O-F = 190 kJ/mol