Question

When 442 mg of NO2 is confined to a 150. mL reaction vessel and heated to 300°C, it decomposes by a second-order process. In the rate law for the decomposition of NO2, k = 0.54 1/(M·s).

A) what is the initial reaction rate?
B) what is the reaction rate if the mass of NO2 increased to 728mg?

I typically always put down my work...but I have no idea where to start with this other than converting NO2 to moles? completely lost here...

Answer 1

You know it's second order so your rate=k[NO2]^2
All you do is like you said, find moles, use that to find molarity (convert mL to L) and then plug the concentration into the equation. You're given the k.

Same thing with part B, just changing the concentration :)