Chemistry
posted by Dena .
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 6.2 104/min, what is the halflife(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!!!

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

I don't know the correct answer that's what i have to find.
for the first part here is my work.....
6.2e4/min=0.0372seconds
half life: t_1/2=0.693/0.372s
=18.6sec*1min/60sec=0.310min (which is not right!) 
Since the problem asks for the halflife 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 = ??