)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.

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.