Advertisements
Advertisements
Question
A first order reaction takes 20 minutes for 25% decomposition. Calculate the time when 75% of the reaction will be completed.
(Given : log = 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)
Advertisements
Solution
For a first order reaction
`t = 2.303/k log [R]_0/[R]`
`k = 2.303/"20 min" log 100/(100 - 25)`
`= 2.303/"20 min" log 4/3`
`= 2.303/"20 min" (log 4 - log 3)`
`= 2.303/"20 min" (0.6021 - 0.4771)`
= 1.44 x 10-2 min-1
The time when 75% of the reaction completed can be calculated as
`t = 2.303/k log 100/(100 - 75)`
`= 2.303/(1.44 xx 10^(-2)) log 4`
`= 2.303/(1.44 xx 10^(-2)) (0.6021)`
= 96.3 min (approximately)
APPEARS IN
RELATED QUESTIONS
For the decomposition of azoisopropane to hexane and nitrogen at 543 K, the following data are obtained.
| t (sec) | P(mm of Hg) |
| 0 | 35.0 |
| 360 | 54.0 |
| 720 | 63.0 |
Calculate the rate constant.
Following data are obtained for reaction :
N2O5 → 2NO2 + 1/2O2
| t/s | 0 | 300 | 600 |
| [N2O5]/mol L–1 | 1.6 × 10-2 | 0.8 × 10–2 | 0.4 × 10–2 |
1) Show that it follows first order reaction.
2) Calculate the half-life.
(Given log 2 = 0.3010, log 4 = 0.6021)
A first order reaction is 50% completed in 1.26 × 1014 s. How much time would it take for 100% completion?
State a condition under which a bimolecular reaction is kinetically first order reaction.
The reaction X → product
Follow first order of kinetics. In 40 minutes the concentration of 'X' changes from 0.1 m to 0.025. M. The rate of reaction when concentration of X is 0.01 m is.
Gaseous cyclobutene isomerizes to butadiene in a first order process which has a 'k' value of 3.3 × 10−4 s−1 at 153°C. The time in minutes it takes for the isomerization to proceed 40% to completion at this temperature is ______. (Rounded-off to the nearest integer)
The decomposition of formic acid on gold surface follows first-order kinetics. If the rate constant at 300 K is 1.0 × 10−3 s−1 and the activation energy Ea = 11.488 kJ mol−1, the rate constant at 200 K is ______ × 10−5 s−1. (Round off to the Nearest Integer)
(Given R = 8.314 J mol−1 K−1)
Define first-order reaction.
Write the equation for integrated rate law for a first order reaction.
Show that `t_(1/2)= 0.693/k` for first reaction.
