Please answer all parts of question $2.$ Please include all steps and work for the answers including the correct calculations when needed or asked.

ammonia. Prior to use as a catalyst, the molybdenum nitride should be reduced using hydrogen.

A$)(2$ pts$.)$ List two interstitial elements in the molybdenum nitride catalyst.

melting point, electrical conductivity, ductility, and other mechanical properties $($ultimate compressive

strength, modulus of elasticity, and yield stress$)?$ Speculate as to what might happen to the particle size

of the Mo nitride catalyst particles over time based on one of the boldfaced properties.

B$)(4$ pts$.)$ What positions in a Mo nitride catalyst are likely places for reaction to take place? What effect

does planar density have on the catalytic reactivity of a material? Where might the molecules stick?

C$)(9$ pts$.)$ Assume the diffusivity of nitrogen atoms through Mo nitride obeys the following relationship,

that the Mo nitride has a crystal diameter of $5nm$ and is an active catalyst at $700K,$

and that the activation energy for diffusion is $38000\frac{J}{m}$ole. First, estimate the

diffusivity of nitrogen in $\frac{m^2}{sec}.$

E$)(8$ pts$.)$ Sketch stress$-$strain curves for Mo nitride and Mo metal on the same plot. On EACH curve,

$D=1\mathrm{.}4{10}^{-8**}$exp$(-E_{\text{d}\text{e}\text{t}}({8\mathrm{.}314}^{**}(T))),$ where $D$ for carbon is in $\frac{m^2}{sec}$ and $T$ is in $K.$

label the following: ultimate compressive strength $($UCS$),$ yield stress $($YS$),$ modulus of

elasticity $($E$),$ and rupture stress $($RS$).$ Points will be assigned for getting trends correct.

Then, using the dimensionless group relationship you learned with regard to diffusion, estimate

the amount of time that it would take the nitrogen to diffuse the length of the diameter of

the crystal, assuming that if the dimensionless group is approximately one, then the

nitrogen atom had sufficient time to diffuse across the entire diameter of the crystal.

F$)(4$ pts$.)$ Properties of materials are also, of course, dependent on how you process them. Use greater

than, less than, or equal signs to indicate whether a material cooled from the liquid

state will have superior properties if cooled quickly or cooled very slowly.

Ductility

Corrosion resistance

Ulitimate compressive strength

Melting point

Cooled quickly Cooled very slowly

Cooled quickly Cooled very slowly

Cooled quickly Cooled very slowly

Cooled quickly Cooled very slowly