The environmental remediation of chlorophenol involves oxidation with hydrogen peroxide to produce steam, hydrochloric acid, and carbon dioxide inside a cold worked and annealed zirconium 702 (properties under miscellaneous nonferrous alloys) reactor. C6H5ClO + 13 H2O2 → 6 CO2 + HCl + 15 H2O In the short term, you have to make a temporary replacement of a non-zirconium thermocouple (temperature-measuring device) to control the temperature at 380oC and 250 atm. The reactor is located outdoors and is operated in batch mode, and in order to halt the reaction, NaOH is added, the neutralized products are emptied, and the reactor is readied for the next batch of chlorophenol to destroy. When H2O2 decomposes, it does generate H2 gas as an intermediate before that hydrogen gets consumed in the reaction.

1) (5 pts.) A) What factors might lead to any type of failure for the reactor or reaction?

(5 pts.) B) Associate each factor from part A with a failure mechanism.

(5 pts.) C) What can you do to prevent the scenario described in A) from failing?

(12 pts.) D) Look up the properties of “zirconium, reactor grade 702” alloy in appendixb.pdf under Miscellaneous Nonferrous Alloys. Calculate the energy per unit volume necessary for reactor explosion, presuming no cracks. You do not need an area or thickness. As part of this problem, sketch the stress vs. strain diagram.

E) (5 pts.) After many years of using the reactor, the reactor now has a 0.001 m long crack. Calculate the maximum possible stress that the reactor can now handle. Did the crack lower the amount of stress that could handle, and if so, did it lower the stress enough to make the reactor “brittle”? Assume KIC = 10 MPa * m0.5 for zirconium 702.
2) Cubic b-BN has a structure consistent with ZnS. In later parts, BE CONSISTENT WITH PREVIOUS ANSWERS.

A) (2 pts.) Determine the electronegativities of B and N. See the electronegativity table.

EN(B) = EN(N) =

B) (2 pts.) Calculate the percent ionic character of a B-N bond.

C) (2 pts.) Classify the B-N bond as an ionic, covalent, hydrogen, or metallic bond.

D) (2 pts.) Use the accompanying table to determine the bond radii for B and N in BN?

Bond radius for B = Bond radius for N =

E) (1 pt.) What are the coordination numbers for both B and N?

F) (6 pts.) Determine the relationship between the lattice parameter, a, and the radii of the

B and N atoms (or ions). You may want to do part G first.

G) (4 pts.) Sketch the (022) plane for BN.

H) (4 pts.) Determine the planar density of the (022) BN plane. Express your answer as

a decimal (not in terms of “a”, the lattice parameter).

I) (4 pts.) Determine the bulk density of cubic b-BN in g/cm3. At. mass B = 10.811 g/mole. At. mass N = 14.007g/mole. Avogadro’s # = 6.022 x 1023 atoms/mole of atoms.

J) (2 pts.) Would the (022) BN plane be seen by XRD? Briefly explain your answer.