logo

Ask Questions, Get Answers

 
X
 Search
Want to ask us a question? Click here
Browse Questions
Ad
0 votes

A certain first order reaction proceeds through t first order kinetics. The half-life of the reaction is 180 s. What percent of the initial concentration remains after 900s?

$\begin{array}{1 1} 3.12 \% \\ 6.24\;\% \\ 1.56\% \\ 9.36\;\% \end{array}$

Can you answer this question?
 
 

1 Answer

0 votes
Answer: 3.12%
From the integrated rate law for a first order reaction, $ [A] = [A]_0\; e^{-kt}$.
The half life $t_{1/2} = \large\frac{ ln\;2}{k}$$ = \large\frac{0.693}{k}$. Given $t_{1/2} = 180\;s \rightarrow k = \large\frac{0.693}{180\;s}$ $ = 0.00385 s^{-1}$
The fraction remaining is the concentration divided by the initial concentration $ = \large\frac{[A]}{[A_0]}$$ = e^{kt} = e^{0.00385 s^{-1} \times 900\; s}$$ = 0.0312 = 3.12\%$
answered Jul 24, 2014 by balaji.thirumalai
edited Jul 24, 2014 by balaji.thirumalai
 

Related questions

Ask Question
student study plans
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...