It's C. Compounds are broken down.
Answer:
a)1.404 E-10 m^2/s
b)1.438 E-12 m^2/s
Explanation:
Diffusion Coefficients can be calculated at different temperatures taking into account the energy of the diffusive process, remember that this process takes place in the interstices of the solid, and gets with higher temperatures due to the higher kinetic energy of the particles.

a) For α-iron (BCC)

b) For γ-iron (FCC)

Answer:
A compond is made up of 2 or more elements that are both DIFFERENT so the answer is B.
Explanation:
Aurous is a cation of gold. Gold takes the name "aurum" (Au) with atomic number of 79. In its purest form, the element is bright, slightly yellow, soft, ductile, and malleable. The charge of aurous is +1. Sulfide, on the other hand, has a charge of -2.
Hence, the chemical formula of the compound is Au₂S and its systematic name is gold (I) sulfide.