)nitrogen from a gaseous phase is to be diffused into pure iron at 700°c. if the surface concentration is maintained at 0.12 wt% n, what will be the concentration (in weight percent) 4.5 mm from the surface after 8.0 h? the diffusion coefficient for nitrogen in iron at 700°c is 4.6 × 10-10 m2/s.

Ineed to find the answer of this question because i dont understand it

What are four significant sources of ghgs that come from wostem washington?

Imagine that a new planet is discovered with two moons of equal mass: moon a and moon b. the mass of the new planet is greater than the combined mass of its moons. moon a is farther away from the new planet than moon b. what is the planet's gravitational pull on moon a compared to the planet's gravitational pull on moon b? the planet's gravity repels moon a with a greater force than it repels moon b, which is why moon a is farther away. the gravitational pull on moon b is greater than on moon a because moon b is closer to the new planet than moon a. the gravitational pull on moon b is greater than on moon a because moon b is farther away from the new planet than moon a. the gravitational pull on moon a is the same as the gravitational pull on moon b because distance does not affect the planet's gravity.