Help!! how do I find c) and d) for this homework assignment. I've been looking through my textbook but no luck onto how I can figure the answer! http://i50.tinypic.com/34dna5c.jpg

How do I find the [ ] of O2 of each time?
& How to calculate the total pressure in the system at 400s?

Question

Help!! how do I find c) and d) for this homework assignment. I've been looking through my textbook but no luck onto how I can figure the answer! http://i50.tinypic.com/34dna5c.jpg  

How do I find the [ ] of O2 of each time?
& How to calculate the total pressure in the system at 400s?

jfraser · Answer

the concentration of O2 at each time will be stoichiometrically related to the amount of N2O5 LOST over that time...

kittykitty04 · Answer

How do I do that? :S

jfraser · Answer

If you consider a generalized reaction like:$$A(g) + 2B(g) \rightarrow AB_2(g)$$
every mole of A that reacts forms 1 mole of AB2, so if, after 100s, 0.5mol of A was USED, then 0.5mol of AB2 should be FORMED.

Use your reaction and the moles of N2O5 lost to find the moles of O2 formed over that time frame.