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									A. Mixon                                 Exam 1B: CH131 Winter 2005

Name:______________________________________________ Date:_______________________________

                                         Equations and Conversions

                     oF   = 9/5oC + 32                    1 cm3 = 1 ml                 12 in = 1 foot

                     oC
                                                          1 kg = 2.205 lb              5,280 ft = 1 mi
                          = 5/9[oF-32]
                                                          1 in = 2.54 cm          1 amu = 1.6606 x 10-24 g
                    NA = 6.022 x 1023

                     pH = -log[H+]




                                                    Solubility:
1.   All common compounds of Group I and ammonium ions are soluble.
2.   All nitrates , acetates, and chlorates are soluble.
3.   All binary compounds of the halogens Group VIIA (other than F) with metals are soluble, except
     those of silver, mercury (I), and lead.
4.   All sulfates are soluble, except those of barium, strontium, calcium, lead, silver, and mercury (I). The
     latter three are slightly soluble.
5.   Except for rule 1, carbonates, hydroxides, oxides, silicates, and phosphates are insoluble.
6.   Sulfides are insoluble except for calcium, barium, strontium, magnesium, sodium, potassium, and
     ammonium.


SHOW ALL WORK!!! NO WORK, NO CREDIT!! SHOW ALL WORK!!! NO WORK, NO CREDIT!!
SHOW ALL WORK!!! NO WORK, NO CREDIT!! SHOW ALL WORK!!! NO WORK, NO CREDIT!!
SHOW ALL WORK!!! NO WORK, NO CREDIT!! SHOW ALL WORK!!! NO WORK, NO CREDIT!!

     1.) Identify the following as physical or chemical changes (6 pts):

            a. Ice melting

            b. Rust forming on your car

            c. Breaking rocks into smaller pieces

            d. Pennies tarnishing

            e. Oil floating on water

            f.   Burning logs in a fireplace




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A. Mixon                              Exam 1B: CH131 Winter 2005

   2.) Convert 122.5oC to oF and K (3 pts)




                         meters           miles
   3.) Convert 15.2                  into       (4 pts)
                      microseconds 2
                                           hr 2




   4.) How many significant figures in 1507.4120 (1 pts)




  5.)   Element X has 50 protons and exists as an ion with 48 electrons. Identify the element and write
        its symbol including the mass number, atomic number and charge (4 pts)




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A. Mixon                              Exam 1B: CH131 Winter 2005

  6.)   Calculate the molar mass of saccharin, C14H8CaN2O6S2, the principle component in Sweet n Low
        (3 pts)




   7.) Calculate the number of protons, neutrons, electrons, and determine the identity for (5 pts):

                Species         # of Protons         # of Neutrons          # of Electrons
                  24Mg+2

                     31S-2

                                      4                                           4

   8.) Give the name of the element from the following symbols (7 pts):

           a. C

           b. K

           c. S

           d. F

           e. Mn

           f.   Se

           g. Si


   9.) Write molecular formulas for the following compounds (8 pts):

           a. Chromium (II) nitrite


           b. Diboron heptanitride


           c. Carbon tetrachloride

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A. Mixon                              Exam 1B: CH131 Winter 2005


           d. Aluminum sulfate



10.) Name the following compounds (8 pts):

           a. CO

           b. P2Br4

           c. Ca(OH)2

           d. Li2S



 11.)   Given the following isotopic data, calculate the average atomic mass for magnesium. A new
        fictitious element is discovered on campus, and has been named Clarkium (Ck). Several
        isotopes have been found, and their relative abundances have been determined:

                             Isotope             Mass           % Abundance
                            Ck – 305          304.982 amu           31.68
                            Ck – 306          306.053 amu           37.62
                            Ck – 308          307.997 amu           30.70
                   Using this data, find the average atomic weight of Clarkium (Ck). (8 pts)




12.) How many atoms of carbon are in 12.92 g of diethyl ether, C4H10O? (4 pts)




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A. Mixon                               Exam 1B: CH131 Winter 2005


13.)   What is the mass percent of nitrogen in Red Dye #40 which has a molecular formula of
       C18H16N2S2O6? (3 pts)




14.)   Lactic acid forms in muscle tissue and is responsible for muscle soreness after exertion. Elemental
       analysis shows that it contains 40.0% mass C, 6.71% mass H, and 53.3% mass O. Determine the
       empirical formula for lactic acid (6 pts)




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A. Mixon                                Exam 1B: CH131 Winter 2005

15.)   Complete the following chemical reactions and balance each. Predict whether a precipitation
       reaction will occur in each of the following cases. IF (and only if) a precipitate forms, write the
       ionic and net-ionic equations: (9 pts)

              a.) NaNO3 + Cu2SO4        →

              ionic:


              net-ionic:


              b.) K2CO3 + CdBr2 →

              ionic:


              net-ionic:


              c.) Pb(OH)4 + KCl →

              ionic:


              net-ionic:


16.)   Calculate the pH or the [H+] concentration for each of the following:
           a. pH = 8.45 (2 pts)
           b. [H+] = 4.56 x 10-3 M (2 pts)




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A. Mixon                              Exam 1B: CH131 Winter 2005

17.)   Given the following equation, calculate the number of milligrams of H2O (l) that will be produced
       from 18.25 grams of H2 (g) and 18.25 grams of O2 (g). (5 pts)

                            ________O2 (g) + ________H2 (g) → ________H2O (l)




                   Which reactant is the limiting reactant:___________________ (2 pts)


18.)   You want to make 450.00 mL of a solution that is 3.33 M K3PO4. Describe exactly how you would
       do this starting from solid K3PO4 (5 pts)




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A. Mixon                             Exam 1B: CH131 Winter 2005


Bonus: (2pts) Explain the major contribution to the changing structure of the atom by either Thomson or
Rutherford. Draw a picture of their “theory” for the structure of the atom.




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