# Chemistry

posted by .

Half-life

N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?

• Chemistry -

Didn't I do this a couple of days ago for you?
k = 0.693/t1/2
Substitute and solve for k.

ln(No/N) = kt
Set any convenient number, such as 100, for No.
N, then, is 1.1% No. For No = 100, N = 1.10
k = from above.
t = solve for t in seconds.

• Chemistry -

Please do not answer this post. This question is a part of the MIT edx 3.091 solid state chemistry curriculum, and posting or using this information is in direct violation of the honor code. Thank you :)

• Chemistry -

Thank you DrBob222,

the fraction left after t seconds is (1/2)^(t/1234)

(1/2)^(t/1234) = 0.011
t = 8028.84

## Similar Questions

1. ### Chemistry

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 …
2. ### Chemistry

A reaction is first order and it takes 324 minutes for the reaction to be 50.0% complete. How long will it take for the reaction to be 85.0% complete at the same temperature?
3. ### Chemistry

Your Open Question Show me another » Chemistry help needed... Confused?
4. ### Chemistry

N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?
5. ### chemistry

N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?
6. ### chemistry

N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?
7. ### Chemistry

The decomposition of N2O5(g) --> NO2(g) + NO3(g) proceeds as a first order reaction with a half-life of 30.0 seconds at a certain temperature. If the initial concentration [N2O5]0 = 0.400 M, what is the concentration after 120 seconds?
8. ### Chemistry

Dinitrogen pentoxide, N2O5, decomposes by first-order kinetics with a rate constant of 0.15 s-1 at 353 K. (a) What is the half-life (in seconds) for the decomposition of N2O5 at 353 K?
9. ### Chemistry

Dinitrogen pentoxide, N2O5, decomposes by first-order kinetics with a rate constant of 0.15 s-1 at 353 K. (a) What is the half-life (in seconds) for the decomposition of N2O5 at 353 K?
10. ### Chemistry

A first-order reaction has a half-life of 26.4 seconds. How long does it take for the concentration of the reactant in the reaction to fall to one-eighth of its initial value?

More Similar Questions