Question

I've tried this problem over and over again, but im not getting the right answers! This is the problem.......

Dinitrogen pentoxide, N2O5, decomposes when heated in carbon tetrachloride solvent.
N2O5 ¨ 2 NO2 + 1/2 O2(g)

If the rate constant for the decomposition of N2O5 is 6.2 10-4/min, what is the half-life(in Minutes)? (The rate law is first order in N2O5.)
How long would it take for the concentration of N2O5 to decrease to 6.250% of its initial value(in minutes)?
How long would it take to reach 0.8% of its initial value(in minutes)?
Can anyone help me? Thank You!!!

Answer 1

You've tried it over and over? Show us your work. And what is the correct answer?

Answer 2

I don't know the correct answer that's what i have to find.

for the first part here is my work.....
6.2e-4/min=0.0372seconds
half life: t_1/2=0.693/0.372s
=18.6sec*1min/60sec=0.310min (which is not right!)

Answer 3

Since the problem asks for the half-life in minutes, I wonder why you converted to seconds then back to minutes? Have you tried leaving the rate in min?
t(1/2) = 0.693/6.2 x 10^-4 = ??