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					Candidate’s Student Identification number: ..........................................


Final mark (/72):                                     ..........................................



                                                                                                      Pages:    9


                                                                                                   Questions:   6
                                                                                                   Section A:   4
                                                                                                   Section B:   2



                                     UNIVERSITY OF TASMANIA




                                         MID SEMESTER TEST


                                                  April 2004




                                               KRA170
                                         Chemistry of Materials




                         Examiners: Prof Allan Canty, Dr Trevor Lewis



                                        Time allowed: 50 minutes



               Answer ALL (six) questions. All questions are of equal mark value.
        2                                               KRA170 Chemistry of Materials Mid-semester Test 2004




 H                                   PERIODIC TABLE OF THE ELEMENTS                                             He
1.008       2                               with Atomic Weights                13    14    15    16    17      4.003
 Li         Be                                                                  B     C     N     O     F       Ne
6.941 9.012                                                                   10.81 12.01 14.01 16.00 19.00 20.18
 Na         Mg                                                                 Al    Si     P     S    Cl       Ar
22.99 24.31        3     4     5     6     7     8      9     10   11    12   26.98 28.09 30.97 32.07 35.45 39.95
 K          Ca    Sc    Ti     V    Cr    Mn     Fe    Co     Ni   Cu    Zn    Ga    Ge    As    Se    Br       Kr
39.10 40.08 44.96 47.87 50.94 52.00 54.94 55.85 58.93 58.69 63.55 65.39 69.72 72.61 74.92 78.96 79.90 83.80
 Rb         Sr     Y    Zr    Nb    Mo    Tc     Ru    Rh     Pd   Ag    Cd    In    Sn    Sb    Te     I       Xe
85.47 87.62 88.91 91.22 92.91 95.94 98.91 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3
 Cs         Ba    *La   Hf    Ta    W     Re     Os     Ir    Pt   Au    Hg    Tl    Pb    Bi    Po    At       Rn
132.9 137.3 138.9 178.5 180.9 183.8 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 210.0 210.0 222.0
 Fr         Ra    †Ac   Rf    Db    Sg    Bh     Hs    Mt
223.0 226.0 227.0 261.1 262.1 263.1 264.1 265.1        268


        *
                  Ce    Pr    Nd    Pm    Sm    Eu     Gd     Tb   Dy    Ho    Er    Tm    Yb    Lu
                 140.1 140.9 144.2 146.9 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0
        †
                  Th    Pa    U     Np    Pu    Am     Cm    Bk    Cf    Es    Fm    Md    No    Lr
                 232.0 231.0 238.0 237.0 239.1 241.1 244.1 249.1 252.1 252.1 257.1 258.1 259.1 262.1
KRA170 Chemistry of Materials Mid-semester Test 2004                                           3

Section A                                                                   Prof Allan Canty


Question 1
a   Show the electron configuration for the nitrogen atom, including the relative energies of
    the orbitals.
                                                                                      [6 marks]




b    Show how ionisation energy changes on going down groups in the periodic table, and
     account for any trends.
                                                                                  [6 marks]




                                                                                         /12
4                                            KRA170 Chemistry of Materials Mid-semester Test 2004

Section A                                                                     Prof Allan Canty


Question 2
a   How does electronegativity vary within the elements of group 16, and how does this
    account for physical properties of compounds formed by these elements? Provide an
    example with your answer.
                                                                                   [6 marks]




b    Silicon carbide, boron nitride, and tin are able to form structures similar to diamond.
     Account for this observation and draw typical structures.
                                                                                         [6 marks]




                                                                                            /12
KRA170 Chemistry of Materials Mid-semester Test 2004                                              5

Section A                                                                     Prof Allan Canty


Question 3
a   Draw three types of cubic unit cell, and explain how many atoms are within each cell.
                                                                                    [6 marks]




b    Describe two types of solution alloy and discuss factors that lead to each type of structure.
                                                                                        [6 marks]




                                                                                            /12
6                                          KRA170 Chemistry of Materials Mid-semester Test 2004

Section A                                                                  Prof Allan Canty


Question 4
a   Draw a phase diagram for metals A and B in which a eutectic is formed at a concentration
    of 60% A, and describe what happens when a liquid solution containing 60% B is cooled.
                                                                                   [6 marks]




                                                        2-                          4-
b    Draw electron dot structures for the carbonate (CO3 ) and silicate anions (SiO4 ),
     showing your reasoning.
                                                                                    [6 marks]




                                                                                          /12
KRA170 Chemistry of Materials Mid-semester Test 2004                                              7

Section B                                 Equilibria                           Dr Trevor Lewis


Question 1
a   For the formation of ammonia from nitrogen and hydrogen given by:
              N2(g) + 3H2(g) <----> 2 NH3(g),
    it was found that Kp = 4.51 x 10-5 at 480 0C. Is the mixture at equilibrium when the partial
    pressures of the gases are PNH3 = 105 atm, PN2 = 35 atm and PH2 = 495 atm? If not, in
    what direction does the reaction need to proceed to reach equilibrium?
                                                                                      [6 marks]




b    If the system in part (a) is allowed to come to equilibrium in a closed vessel, what would
     be the effect of removing ammonia from the vessel?
                                                                                         [6 marks]




                                                                                            /12
8                                          KRA170 Chemistry of Materials Mid-semester Test 2004

Section B                               Equilibria                          Dr Trevor Lewis


Question 2
a   The solubility of lead iodide (PbI2) is found experimentally to be 0.06 g/L. What is its
    Ksp?
                                                                                    [6 marks]




b    Given that the Ksp of manganese(II) hydroxide (Mn(OH)2) is 1.6 x 10-13, calculate the
     solubility in g/L of Mn(OH)2 in water buffered at pH 9.5.
                                                                                     [6 marks]




                                                                                         /12
KRA170 Chemistry of Materials Mid-semester Test 2004   9




         Section       A                  B
                      Canty             Lewis


Q1 /12




Q2 /12




Q3 /12




Q4 /12




Totals




Grand Total
/72

				
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