• Post a New Question
• Current Questions
• Chat With Live Tutors

Homework Help: Chemistry

Posted by Anonymous on Thursday, January 31, 2013 at 1:59pm.

Calculate the half-life (in s) of a first-order reaction if the concentration of the reactant is 0.0655 M 18.4 s after the reaction starts and is 0.0173 M 41.2 s after the reaction starts.

I got 25.6

Suppose the half-life is 23.7 s for a first order reaction and the reactant concentration is 0.0709 M 60.1 s after the reaction starts. How many seconds after the start of the reaction does it take for the reactant concentration to decrease to 0.0154 M?

I got 79.05.

Any help is appreciated!

• Chemistry - DrBob222, Thursday, January 31, 2013 at 3:40pm

  I did #1 as
  ln(0.0655/0.0173) = kt, the
  k - 0.693/t_1/2 and did not obtain 25.6 s.
  
  Use ln(No/N) = kt for #2.
  I did't obtain 79 s for that.
  Post your work for both of these and I'll look for the error.
  

• Chemistry - Anonymous, Thursday, January 31, 2013 at 8:20pm

  So is it ln(.0655/.0173) and then the answer over .0693 which is k to get 1.24?
  

• Chemistry - Anonymous, Thursday, January 31, 2013 at 8:25pm

  and how do you find k? because for the second problem i did ln (.0709/.0154) to get 1.527 which is obviously not the answer.
  

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

Chemistry - if the initial concentration of the reactant in the first order ...
chemistry - calculate the half-life of a first- order reaction if the ...
chemistry - calculate the half-life of a first- order reaction if the ...
chemistry - A particular reactant decomposes with a half-life of 103 s when its ...
Chemistry(Please check) - 8. The half-life of a reaction was found to be ...
chemistry - The half-life of a reaction was found to be inversely dependent on ...
chemistry - The half-life of a reaction was found to be inversely dependent on ...
chemistry - The half-life of a reaction was found to be inversely dependent on ...
Chemistry - The rate of a first-order reaction is followed by spectroscopy, ...
Chemistry - The rate of a first-order reaction is followed by spectroscopy, ...

For Further Reading