Nitrogen pentoxide decomposes according to equation :
`2N_2O_5(g)to4NO_2(g)+O_2(g)`
This first order reaction was allowed to proceed at `40C` and the data below were collected:

(a) Calculate· the rate constant. Include units with your answer.
(b) What will be the concentration of `N_2O_5` after 100 minutes
(c) Calculate the initial rate of reaction.

Explanation

(a) `k=2.303/tlog.[A]^@/([A])`
`k_1=2.303/tlog. 0.400/0.289`
`rArr=2.303/20log. 1.384=2.303/20xx0.144=0.01625 min^(-1)`
`k_2=2.303/40log. 0.400/0.209rArr2.303/20xx0.144=0.01625 " min"^(-1)`
`k_3=2.303/60log. /0.151rArr2.303/60xx0.4231=0.016236 " min"^(-1)`
`k_("average")=(0.01625+0.01623+0.01623)/3
=0.016236" min"^(-1)`
(ii) `k=2.303/100 log. 0.400/([A])=(1.6236xx10^(-2)xx100)/2.303log. 0.4/([A])`
antulog `0.705=0.4/([A])`
`0.4/([A])=5.070rArr[A]=0.07889M`
(iii) `"Rate"=k[N_2O_5]`
`=0.016236xx0.4=0.00649" mol "L^(-1)s^(-1)`