Advertisements
Advertisements
Question
Solve
A first-order reaction takes 40 minutes for 30% decomposition. Calculate its half-life.
Advertisements
Solution
Given:
[A]0 = 100%, [A]t = 100 - 30 = 70%, t = 40 min
To find:
Half life of reaction (t1/2)
Formula:
`"k" = 2.303/"t" "log"_10 ["A"]_0/["A"]_"t"`
Calculation:
Substitution of these in above
`"k" = 2.303/"t" "log"_10 100/70`
= `2.303/"40 min" "log"_10 (1.429)`
= `2.303/"40 min" xx 0.155`
= 0.008924 min-1
t1/2 = `0.693/"k" = 0.693/(0.008924 "min"^-1) = 77.66 "min"`
The half life of reaction is 77.66 min.
APPEARS IN
RELATED QUESTIONS
How will you represent first order reactions graphically.
Solve
The half-life of a first-order reaction is 1.7 hours. How long will it take for 20% of the reactant to react?
Answer the following in brief.
What are the units of the rate constant?
Time required for 100% completion of a zero order reaction is _______.
Write a mathematical expression for integrated rate law for zero-order reaction.
The rate constant of the first order reaction is 1.386 min–1. Calculate the time required for 80% reactant to decompose?
A zero-order reaction \[\ce{X -> Product}\], with an initial concentration 0.02 M has a half-life of 10 min. if one starts with concentration 0.04 M, then the half-life is
The decomposition of phosphine (PH3) on tungsten at low pressure is a first-order reaction. It is because the
For a first-order reaction, the rate constant is 6.909 min−1 the time taken for 75% conversion in minutes is
The rate constant of a reaction is 5.8 × 10−2 s−1. The order of the reaction is ____________.
Write the rate law for the following reaction.
A reaction that is `3/2` order in x and zero order in y.
The integrated rate law is a direct relationship between ____________ and ____________.
The following reactions follow zero order kinetics, EXCEPT ____________.
For first order reaction the concentration of reactant decreases from 0.2 to 0.1 M in 100 minutes. What is the rate constant of the reaction?
The time of completion of 90% of a first order reaction is approximately ____________.
The integrated rate equation for first-order reaction, A → product, is ______.
For the first order reaction, plot of log10 [A]t against time 't' is a straight line with a negative slope equal to ____________.
The rate and the rate constants of the reaction, \[\ce{A + 2B -> C + D}\] are 8 × 10−3 mol dm−3 s−1 and 2 × 10−3 s−1 respectively. The concentrations of A and B are 4 mol dm−3 each. The overall order of the reaction is ____________.
The order of the reaction for which the unit of rate constant is s−1 is ____________.
Half-life period of a first order reaction, \[\ce{A -> product}\] is 3.0 hours. What is the value of rate constant?
Which among the following is an example of zero order reaction?
Which among the following is an example of pseudo first order reaction?
A first order reaction takes 40 minutes for 30% completion. Calculate the half-life of reaction.
What is the unit of rate constant for the zero order reaction?
Half-life of first-order reaction \[\ce{X -> Y + Z}\] is 3 minutes. What is the time required to reduce the concentration of 'X' by 90 % of it's initial concentration?
Obtain the expression for half-life and rate constant of the first-order reaction.
Which one of the following reactions is a true first-order reaction?
The rate constant and half-life of a first order reaction are related to each other as ______.
The rate constant for a first order reaction is 7.0 × 10-4 s-1. If initial concentration of reactant is 0.080 M, what is the half-life of reaction?
