Answer in General Chemistry for dale #166046

The decomposition of NO_2(g) : 2NO_2(g) —–>2NO_(g) +O_(g) is a second order reaction and the rate constant is 0.755L/(mol-s). In an experiment, the initial concentration of NO_2(g) was 0.00650 mol/L. (a)What is the concentration of NO_(g) after 125 seconds have elapsed? (b) How many seconds will it take for the concentration of NO_2(g) to drop to 0.00100 mol/L?

(a) For second order reaction:

“k = frac{1}{t}[frac{1}{A_t} -frac{1}{A_0}] \nn0.755 = frac{1}{125}[frac{1}{A_t} -frac{1}{0.0065}] \nn94.375 = frac{1}{A_t} -frac{1}{0.0065} \nn248.221 = frac{1}{A_t} \nnA_t = 0.00402 ;M”

“(b) ; 0.755 = frac{1}{t}[frac{1}{0.00100} -frac{1}{0.0065}] \nn0.755 = frac{1}{t}[1000 u2013 153.84] \nn0.755 = frac{846.16}{t} \nnt = 1120 ;s”