Ch. 6 & 7  atomic structure & periodic trends             test     [85points]        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 may lose points.

               

 

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.  Describe and rationalize the periodic trends in the electron affinity in a row in the periodic table.  [10 points]

 

2.  .   lab related questions.  [20 points]

 

a.  Which is the better color, red or green, to measure the absorption of a green-colored solution ?  Justify / rationalize your choice.

 

b.  Based on the following hypothetical experimental data

 

[Cu+2]  (mM)

Absorbance

0

0

100

.12

200

.24

300

.36

 

generate and use a calibration curve to estimate the [Cu+2] of a sample, where its absorbance = 0.3.

 

c.  Based on the following hypothetical graph,

abs spectrum

              what would be the “best” wavelength to use for a calibration curve ?  Justify / rationalize your choice.

 

 

3.  In the hydrogen atom, an electron goes from the n = 4 to n = 3 electron energy level.  [15 points]

 

a.  What is the preceding event – the absorption or emission of light ?  Justify your answer.

 

b.  The wavelength of visible light is from 400 – 700 nm.  Is the light associated with the preceding event, visible light ?  ultraviolet light ?  infared light ?  Justify your answer.

 


4.  Write the chemical equation for ___; need not balance the chemical equation.  [15 points]

 

a.  add potassium metal to water

 

b.  bubble sulfur trioxide in a solution of sodium hydroxide

 

c.  heat calcium metal in an atmosphere of oxygen

 

d.  sodium metal reacts with chlorine gas

 

e.  potassium metal reacts with oxygen gas

 

 

5.  Pick any 2 of the following choices:  describe ___.  Clearly identify your choice; will evaluate 2 lowest-scoring choices if you do all three choices.  [10 points] 

 

a. aufbau principle

b.  Pauli exclusion principle

c.  Hund’s rule

 

6.  old topics  [15 points]

 

a.  Describe the results of Rutherford’s experiment and its interpretation regarding the atom. 

 

b.  For the reaction, H2  +  O2  à  H2O, the  

 

rate  =  k [H2] [O2]1/2

 

if the rate is 2.5 μM / second, [H2] = 2.0 mM and [O2] = 5.0 mM, then what is the value and units of the rate constant, k ?