Question

Nitrogen dioxide decomposes at 300°C via a second-order process to produce nitrogen monoxide and oxygen according to the following chemical equation. 2 NO2(g) → 2 NO(g) + O2(g). A sample of NO2(g) is initially placed in a 2.50-L reaction vessel at 300°C. If the half-life and the rate constant at 300°C are 22 seconds and 0.54 M-1 s-1, respectively, how many moles of NO2 were in the original sample?

Answer 1

t(1/2)=1/(k[NO2])
[NO2]=1/(kt(1/2))
[NO2]=1/(0.54M-1 s-1*22s) seconds cancel
[NO2]=1/11.88=0.0842
inital mole= 0.0842*volume(2.5)=0.210 mols