CHEM 110
                 Answers to Tenth Take Home Quiz

1. Write a balanced equation for the reaction of sodium metal 
   with water.
    2Na + 2H2O <--->  2Na+  +  H2(g)  +  2OH-

2. Indicate the industrial uses of the following compounds.
     sodium chloride                  sodium carbonate

    production of Cl2                production of glass

3. What is the principal compound found in teeth and bones ?
                        calcium phosphate

4. Which of the following pairs of elements are most similar in 
   the chemical and physical properties ?

    C and Pb     (Na and K)       K and Ca        Al and Cl

5. Write the formula for gypsum ?

    CaSO4ú2H2O

6. Write a balanced equation for the conversion of gypsum into 
   Plaster of Paris ?

    CaSO4ú2H2O <---> CaSO4ú0.5H2O  +  1.5H2O

7. Write the formula for calcium carbonate.

    CaCO3

8. Name some natural materials composed of calcium phosphate.

                  teeth   bones   rock phosphate

9. Write the electronic configurations for a sodium atom, a 
magnesium atom, and an aluminum atom.  Also write electronic 
configurations for a sodium ion, a magnesium ion, and an aluminum 
ion.  Which electrons are lost when these atoms are converted 
into the corresponding ions ?

              Atom                     Ion

    Na     1s22s22p63s1            1s22s22p6

    Mg     1s22s22p63s2            1s22s22p6

    Al     1s22s22p63s23p1         1s22s22p6

    Those in the outermost level .

10. What are the two most important allotropic forms of carbon ?
                       diamond     graphite
    
    Why are these allotropic forms so different ?

           2 dimensional versus three dimensional bonds

11. Name some naturally occurring materials which contains silicon.

             quartz      opal      feldspar      granite