Question

The decomposition of `N_(2)O_(5)` in a carbon tetrachloride solutioin has been investigated.
`N_(2)O_(5)("solution") to 2NO_(3)` (solution) +`1//2O_(2)(g)` ltrbgt The reaction has been found to be of the first order in `N_(2)O_(5)` with a first order rate-constant = `6.2 xx 10^(-4)s^(-1)`. Calculate the rate of the reaction when (a) `[N_(2)O_(5)]` = 1.25 mol `L^(-1)` and b) `[N_(2)O_(5)]` = 0.25 mol `L^(-1)`. c) What concentration of `N_(2)O_(5)` would give a rate of `2.4 xx 10^(-3) mol L^(-1)s^(-1)` ?

Answer 1

a) As the decomposition of `N_(2)O_(5)` in carbon tetrachloride is a first order reaction.
Rate = `k[N_(2)O_(5)]=6.2 xx 10^(-4)s^(-1) xx 1.25 mol L^(-1)`
`=7.75 xx 10^(-4) mol L^(-1)s^(-1)`
b) Rate = `k[N_(2)O_(5)] = 6.2 xx 10^(-4)s^(-1) xx 0.25 mol L^(-1)`
`=1.55 xx 10^(-4)mol L^(-1)s^(-1)`
c) `[N_(2)O_(5)]="Rate"/k = (2.4 xx 10^(-3) molL^(-1)s^(-1))/(6.2 xx 10^(-4)s^(-1))= 3.87 mol L^(-1)`