Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 109

 

Chem 109, Dr. Paselk

Hour Exam II
 Name
Fall 1994

(100 pts)
 Lab

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Show Work on All Problems For Credit!

(15) 1. Briefly define/describe each of the following:

a. Isotope:

 

b. Y2:

 

c. Anion:

 

d. Unit cell:

 

e. Hydrogen bond:

 

(10) 2. Predict the formal charge for each atom in: a) POCl3 and, b) Sodium permanganate. No credit if work is not shown!

a)

 

b)

 

(8) 3. Consider a lone ion of vanadium (III) and provide the requested information. Read carefully!

a. Give a set of quantum numbers for the outermost electron of this ion:

b. How many radial nodes will this electron's wave function (distribution) have?

c. How many angular nodes will this electron's wave function (distribution) have?

d. Should this ion be paramagnetic? Why or why not?

 

(14) 4. Draw Lewis structures for:

a. Sodium chlorate

 

 

b. Bromine trifluoride

 

 

c. Based on your structure for (a) above, predict the molecular geometry of chlorate.

 

 

d. Based on your structure for (b) above predict the electronic geometry around bromine.

 

 

e. What is the molecular shape of Bromine trifluoride?

 

 

(10) 5. Find the requested concentrations in the solutions described below. Show work for credit!

a) Calculate the molarity of a solution made up by dissolving 56.2 g of calcium chloride in water to give a final volume of 500.00 mL.

 

 

b) Find the mole fraction (X) of sodium ions in a 0.200 molal, aqueous solution of sodium chloride.

 

(8) 6. Indicate locations on the sketch of the Periodic table provided when answering the questions below.

Periodic Table of the Elements
 IA IIA IIIA IVA VA VIA VIIA VIIIA
   H  He
Li Be  B Groups  B C N O F Ne
Na Mg IIIB IVB VB VI VIIB VIIIB IB IIB  Al Si P S Cl Ar
K Ca   Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
 Rb Sr                  Ag  Cd   Sn     I  Xe
 Cs  Ba        W        Pt Au  Hg    Pb        

                           
                           

a) Draw a box around the lanthanides.

b) Indicate with an arrow the group with highest electron affinities.

c) Show with an arrow the trend, from highest to lowest, of electronegativities

d) "Circle" the non-metals

(10) 7. Twenty five grams of a non-electrolyte is dissolved in 469.0 g of water. The resultant solution was found to have a boiling point of 100.58 °C at one atmosphere of pressure. Find the apparent molecular mass of this substance. (The boiling point elevation constant for water is 0.512 °C/m.) Show Work!

 

 

(10) 8. Draw and label completely a heating curve for water going from 200 K to 400 K at one atmosphere.

 

 

(15) 9. Write net ionic equations for each of the following: (If there is no reaction write NR)

a. Solutions of silver nitrate and sodium iodide are mixed

 

 

b. Copper sulfate solution is mixed with excess ammonia.

 

 

c. Acetic acid is mixed with a solution of sodium hydroxide.

 

 

d. Solutions of cadmium (II) chloride and potassium sulfide are mixed.

 

 

e. Hydrochloric acid is poured over zinc metal.

 


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Last modified 18 December 2006